# CTBT Science and Technology Conference 2021 (SnT2021)

Europe/Vienna
28 June - Opening (Hybrid) in Hofburg Palace, Vienna, Austria 29 June to 2 July - Virtual conference
Description

The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) relies on innovation to enhance the capabilities of the Treaty’s verification regime as well as to help move the Treaty closer to universalization and entry into force. As the sixth event in the CTBT: Science and Technology conference series, SnT2021 will bring together around 1000 scientists, technologists, academics, students, CTBTO policy makers, members of the media and representatives of organizations involved in research and development that is relevant to all aspects of Treaty verification.

Conference objectives:

• To identify scientific opportunities and methods for improving nuclear test monitoring and verification;
• To identify how scientific developments and cooperation can support national needs and frame policy objectives in support of the CTBT;
• To broaden and strengthen the engagement of scientific communities working in test ban monitoring, including young scientists, and to enhance geographic and gender representations of these communities;
• To support the exchange of knowledge and ideas between the CTBTO and the broader scientific community;
• To promote the wider civil and scientific applications of techniques and data used for test ban verification;
• To highlight the CTBT’s successful model for multilateral science diplomacy and cooperation.
Surveys
Survey on participation in e-poster round tables
Registration
Registration for the CTBT Science and Technology 2021 Conference (SnT2021)
The SnT Support Team
• Monday, 28 June
• 10:00 12:30
High Level Opening - session 1: High Level Opening Festsaal (Hofburg)

### Festsaal

The Comprehensive Nuclear Test Ban Treaty’s (CTBT) opened for signature 25 years ago. The tested and proven verification regime, built on an over $1 billion investment in the International Monitoring System (IMS), is nearly complete. While the norm against nuclear testing is well established, with recent ratifications by Cuba and Comoros, the Treaty is not yet legally and universally binding. This seeming paradox requires both outside-the-box approaches to achieve the long-sought political breakthrough, as well as scientific and technological advances to sustain, improve and maintain the valuable contributions of the IMS. To mark this important anniversary, the High-Level Opening Day of the Science and Technology Conference 2021 will: • reaffirm the CTBT’s achievements, in obtaining acceptance of a worldwide norm against testing and the technical advances of its verification regime and technologies. • outline the essential role of the CTBT in achieving a world free of nuclear weapons; and • take a journey across time including the CTBT’s origin, its multi-disciplinary present, and concluding with a vision for the future through the lens of artificial intelligence, space travellers, scientists, and the upcoming generation of leaders. • 10:00 [email protected] anniversary of the CTBT: Ceremonial Opening and Political Remarks 1h 10m Master of Ceremony: Ms. Sanam Shantyaei, France24 Speakers list (subject to further updates): • Mr. Josep Borrell, High Representative and Vice President of the European Union • Ms. Ghada Fhati Waly, Director General, UNOV (also delivering a message on behalf of the UN-Secretary General Antonio Guterres) • Mr. Rafael Grossi, Director General, IAEA • Mr. Peter Launsky-Tieffenthal, Secretary General of the Federal Ministry of European and International Affairs of Austria • Mr. Bruno Rodríguez Parrilla, Minister of Foreign Affairs of Cuba • Mr. Lassina Zerbo, Executive Secretary, CTBTO • 11:10 Musical interlude 10m • 11:20 Facilitated dialogue on [email protected] years: Evolution of the CTBT, the Organization and its technologies & CTBT’s model function of inclusion and science cooperation 1h 10m Speakers in alphabetical order. High-level speakers (subject to further updates): • Mr. Ban Ki-Moon, Eighth United Nations Secretary General and Founder of the Ban Ki-Moon Centre for Global Citizens • Mr. Grigory Berdennikov, Ambassador Extraordinary and Plenipotentiary; Head of the Russian Delegation at the CTBT Negotiations; Deputy Minister of Foreign Affairs of the Russian Federation (1992–1993; 1999–2001) • Ms. Tarja Halonen, Eleventh President of Finland • Ms. Anne Strømmen Lycke, Chief Executive Officer of NORSAR • Ms. Jenifer Mackby, Senior Fellow, Federation of American Scientists • Mr. Ernest Moniz, United States Secretary of Energy (2013-2017) • Mr. Jaap Ramaker, Ambassador of the Kingdom of Netherlands and Chair of the 1996 CTBT Negotiations, and former Special Representative to promote the Ratification of the CTBT, 2004 - 2009 CTBTO-CYG • Mr. Jaona Andriamampandry, Assistant Researcher, Institute of Geophysics and Observatory of the University of Antananarivo, Madagascar • Ms. Sitara Noor, Senior Research Fellow, Centre for Aerospace and Security Studies, Islamabad, Pakistan • Ms. Magdalene Wangui Wanyaga, Project Manager, SandRose Ltd, Kenya • 12:30 14:00 Lunch break 1h 30m • 13:00 13:45 CTBTO Youth Group: Evolution of the SnT conferences: CYG dialogue with Executive Secretary Lassina Zerbo • 13:00 Evolution of the SnT Conference: CTBTO Youth Group dialogue with Executive Secretary Lassina Zerbo 45m Since we only see the slow emergence from the COVID pandemic, SnT 2021 has gone mostly virtual. The new format aims to stimulate rich discussions and to create the space for wider and more diverse participation, especially by the next generation of experts. This year’s conference is the sixth conference in the SnT series and coincides with the 25th anniversary of the CTBT since it opened for signature. The principal goal of the conference series remains unchanged – to create a multidisciplinary scientific platform attracting scientists and experts from the broad range of the CTBTO’s underpinning technologies. For an entire week over multiple sessions, they will review scientific and technological advances and anticipate which innovative technologies would further strengthen the Treaty and its verification regime. Since 2015, CTBTO Youth Group (CYG) members have participated in the SnT as speakers, citizen journalists, poster presenters and attendees. To highlight the importance of multi-disciplinary youth engagement, Dr Lassina Zerbo, Executive Secretary of the CTBTO, will engage in an interactive dialogue with the CYGs. Participants will be able to discuss the evolution of the SnT series, the role of youth and learn about the main highlights of the conference. • 14:00 16:30 High Level Opening - session 2: High Level Opening Festsaal (Hofburg) ### Festsaal #### Hofburg • 14:00 Artificial Intelligence (AI) to Transform Nuclear Explosion Monitoring and Verification: Thoughts on Opportunities and What It Might Take to Get There. 45m Abstract: Artificial Intelligence (AI) has the potential to revolutionize the very ways we live our lives and make our world more sustainable and equitable. Today’s AI based methods, which are still nascent and narrowly applied, are already providing means to innovate and impact everything including science, environment, energy, health, and climate. AI impacts the U.S. Department of Energy (DOE) across all missions, businesses, and operations, and has become central to accelerating scientific discovery and the development of transformational new technologies. The DOE, like the CTBTO PrepCom, needs trustworthy AI systems that are accurate with high confidence and proven to be unbiased and reliable. Working in collaboration with global partners, DOE – the largest sponsor of physical sciences in the United States and largest generator of Nobel-prize winning scientists in the world – is driving high-risk research and development to advance the science of AI to create AI-enabled technologies that fulfill these requirements. This presentation will highlight a number of examples of AI in practice at DOE today, emerging areas of interest, and insights on opportunities presented by AI for the CTBTO PrepCom, drawing on decades of experience developing cutting-edge science and technology capabilities to deter and detect nuclear explosive tests. Speaker: Mr Dimitri Kusnezov (US Deputy Under Secretary for Artificial Intelligence and Technology, USA) • 14:45 Musical interlude 10m • 14:55 Space science and technology for global sustainable development, peace, and security 1h 5m Space has become an indispensable tool for our way of life. Addressing global challenges requires utilization of all available assets and space is one. Overall, space has transformed society and is instrumental for sustainable development at large. Today, we are witnessing changes to the conventional ways of operating in space, unlocking an immense range of opportunities, but also leading to challenges, requiring immediate attention and resolution. The dramatic increase in the number and type of actors in space and the consequent rapid growth of satellites have strong implications on the space environment. The United Nations has served as a convener for deliberations on space affairs since the beginning of space activities and has been successful in addressing the most pressing issues. It provides a unique intergovernmental and global platform for the benefit of everyone. Proactive multilateralism within the UN serves not only to expand access to space, but to ensure responsible behaviour in space for the benefit of human mankind. Chaired by Ms. Simonetta di Pippo, Director UN Office for Outer Space Affairs Introductory keynote on “Monitoring our planet from space”: Mr. Josef Aschbacher, Director of the European Office of Space Affairs Panellists [subject to further updates]: • Mr. Jean Loup Chrétien, a retired Général de Brigade in the Armée de l'Air de France and former CNES and NASA astronaute. He was the first Western European in space and the first non-American and non-Russian to perform an extra vehicular activity. • Ms. Ilaria Cinelli, senior engineer with records of accomplishments in biomedical engineering and space exploration • Ms. Zanaib Azim, Co-Founder of G.I.V.E and Youngest Member of Virgin Galactic's Future Astronaut Program • 16:30 16:45 Interlude 15m • 16:45 17:45 European Union panel discussion on Youth: Securing a nuclear test-free world for Youth and the next generations • 16:45 Securing a nuclear test-free world for Youth and the next generations 1h As promoting the universalisation of the CTBT and its entry into force is a political imperative for the EU and also a good example of our efforts to strengthen the rules-based international system, the panel will explore what is the status of youth engagement with respect to the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The panel will also examine how the EU, as a staunch supporter of the CTBT and its Organisation, has contributed to CTBTO efforts to engage youth, and more broadly in the areas of capacity-building. The panellists will finally discuss how the main requests and suggestions from youth to policy makers are to advance the CTBT’s entry-into-force and thus move a step closer to a world without nuclear weapons. • Tuesday, 29 June • 09:30 12:30 e-poster session - day 1: e-poster session - Theme 1 (T1.1, T1.2, T1.3) and T5.3 Online #### Online E-poster session for: - T1.1 - T1.2 - T1.3 - T5.3 • 11:00 11:30 Series of talks on 25 years of CTBT: Seismic technology: Special talk Location 1 (Onlince) ### Location 1 #### Onlince 25 years of CTBT: progress on verification technologies and looking towards the future 25 years and beyond • 11:00 New applications at the IDC for SHI Expert Technical Analysis 30m The Preparatory Commission for the CTBTO (Commission) routinely process time-series data from a global network of seismic, hydro-acoustic, and infrasound (SHI) stations. The data are processed to detect, build, locate, and screen events that may have characterization parameters similar to those from nuclear explosions. The observation and processing systems are required to be sensitive to small (e.g. low-magnitude) events, especially in unusual locations (e.g. aseismic regions). In order to match this requirement and to assist the State Parties to identify the source of specific events the IDC develops services combined in one SHI Expert Technical Analysis (ETA) Suite. The Parametrical Moment Tensor Estimator, ParMT (depth and magnitude determination through the moment tensor estimation) and the IDC historical master event-based Spot Check Tool, SCT, are the ongoing IDC developments. A promising avenue to improve the ParMT results, as well as for enhancement of IDC (mostly regional) locations, is to embrace the Ambient Noise Tomography technique in IDC practice. Receiver velocity models underneath IMS stations can be improved using the vast amount of gathered seismic background data. The same approach can be utilized for OSI data processing using the ANT-based velocity models produced with the noise data from SAMS array. Speaker: Mr Ivan Kitov (CTBTO Preparatory Commission, Vienna, Austria) • 11:30 13:00 Panel discussion on Lessons from historic nuclear test explosions and value of recorded signals for monitoring science: Panel discussion Location 1 (Online) ### Location 1 #### Online • 11:30 Lessons from historic nuclear test explosions and value of recorded signals for monitoring science 1h 30m The nuclear tests announced by the DPRK provided an opportunity to test methods and gain experience with respect to the estimation of the absolute and relative event location, depth and magnitude. However, this experience is limited to one specific test location. Much broader experience can be gained by applying modern analysis methods to the vast amount of data recorded on more than 2000 historic nuclear test explosions. To support such developments, valuable progress towards preserving and making available for research digitized data of historic nuclear explosions has been made. The goal of this session is to identify the priorities for continuing and expanding these efforts. Historic data are needed from as many as possible different regions and geological characteristics. Signals should be preserved from tests in the atmosphere, underwater and underground. While most ongoing efforts focus on seismic data, the historic hydroacoustic and infrasound data are rare and radionuclide data are sparse. Speaker: Mr Rong Song Jih (U.S. Department of State, USA) • 11:31 12:31 Event 1 - Resilience of the CTBT monitoring regime: Event Location 2 (Online) ### Location 2 #### Online • 11:31 Event 1 on Resilience of the CTBT monitoring regime, including lessons learned from the COVID-19 pandemic crisis 1h The COVID-19 pandemic is a major topic of interest for the SnT2021. The global nature of it produced a resilience test for many, and in particular for a global monitoring system, such as the CTBTO’s, that relies on continuous data gathering, transmission and analysis. The objective of this series of two events is to provide the audience with pertinent case histories and lessons learned from IMS stations e.g. during O&M activities, station upgrades or logistics challenges, faced by the station operators and PTS during the restrictions imposed by covid-19. Topics presented in Event 1 are (i) the steps taken to ensure operation and maintenance activities for optimal performance of the IMS stations IS32 and PS24 in Kenya during COVID-19 restrictions, (ii) the upgrade of five auxiliary seismic stations in Japan and how the COVID-19 limitations and restrictions were overcome, (iii) restrictions under the COVID-19 crisis imposed on the operation and maintenance of the radionuclide stations RN37 and RN38 in Japan and how JAEA is working with PTS, manufacturers of RASA and SAUNA, and local operators in order to overcome this challenge, (iv) timeline of the active cases at IS42 infrasound station in the Azores, Portugal, the related constraints and O&M actions taken, with PTS support, to guarantee the Mission Capability of the station. (v) CTBTO/OSI will present a brief review of the OSI Training section’s interventions, designed to mitigate the loss of onsite technical training and achieve and maintain true blended learning during and after COVID-19 and (vi) CTBTO IMS/MFS will share examples of logistics and maintenance cases that could have affected data availability and show contingency measures that were implemented. Speaker: Mr Thomas Ludwig Hoffmann (CTBTO Preparatory Commission, Vienna, Austria) • 13:30 14:30 Highlight talk on the Solid Earth and its Structure: Highlight talk Location 1 (Online) ### Location 1 #### Online • 13:30 Imaging the Earth's Deep Interior using seismic waves 1h Forty years ago, the first global seismic tomographic models revealed the presence of two large, antipodal, structures at the base of the Earth's mantle, now known as "large low shear velocity provinces" (LLSVPs), that had no obvious relation to surface geology or mantle dynamics as understood from plate tectonics theory, and as reflected in near surface seismic structure. With the expansion of digital, very broadband seismic networks and related on-line databases, combined with improvements in theory and computer power, the resolution of mantle elastic structure has progressively improved. In this lecture, I will illustrate how state-of-the-art imaging techniques allow us to: track the fate of tectonic plates that dive back into the mantle beneath the Pacific "ring of fire", improve our understanding of the morphology and role of the LLSVPs, and follow the paths of deeply rooted hot mantle plumes, as they ascend towards the surface and are expressed there in the form of hotspot volcanism (of which Hawaii and Iceland are prominent examples). I will present some of the open science questions, technical challenges for further progress in full waveform tomography, as well as possible paths ahead to address them, combining tools from seismology and other geophysical disciplines. Speaker: Ms Barbara Romanowicz (University of California, Berkeley, CA, USA) • 13:30 15:30 T2.4 - Atmospheric and Subsurface Radionuclide Background and Dispersion: Oral session Location 2 (Online) ### Location 2 #### Online oral session • 13:30 Session introduction 5m • 13:35 Six months of radioxenon detections by the SPALAX New Generation system near Paris in 2019 15m As part of its qualification process by the PTS, the SPALAX-NG - noble gas - New Generation system was operated from October 2018 to April 2019 on the CEA/DAM premises near Paris (France). The new generation system’s high performances contribute significantly to increase the number of detections and to improve the knowledge of the radioxenon background. Indeed, in this study, a major dataset including numerous isotopic ratios is established for Western Europe that enables to refine the characterization of the background sources and the discrimination criteria. In addition, a full Atmospheric Transport Modelling study has been performed from this full dataset, that allows to 1/ reconsider the radioxenon source terms of the main emitter in Western Europe (IRE, Fleurus, Belgium), and to 2/ detect for the first time some very local and non-traditional sources that can influence the categorization of a detection. Speaker: Mr Pascal Achim (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France) • 13:50 Statistical study of the IMS 133Xe data distributions, using both a parametric and a non-parametric method 15m The aim of this work is to apply both a parametric and a non-parametric statistical method to the 133Xe activity concentrations measured at noble-gas stations of the IMS of the CTBTO, in order to investigate the atmospheric background and the anomalous values. The parametric method consists of two control charts: a single-observation chart sensitive to large variations with respect to the mean value, and an EWMA chart sensitive to small variations with respect to the mean value. The results show that the control charts could be useful for an NDC carrying out daily monitoring to easily detect significant variations of the activity concentrations, and to perform more specific analysis of the anomalous values. The parametric method is expected to be useful to better understand the false positives. The non-parametric method is based on a Recursive Segmentation and Permutation (RS/P) algorithm, it does not require any assumption about the underlying probability distribution, and it associates a significance level to the results. The RS/P method is useful for detecting single or multiple mean shifts and/or scale shifts, and the results show that it can be useful to highlight any random oscillations of the phenomenon providing a likely better understanding of anomalous values. Speaker: Mr Giuseppe Ottaviano (Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Italy) • 14:05 Statistical study of the Cs-137 detections at RN43 station 15m This work is the result of a joint collaboration between the Italian and the Mauritanian National Data Centers. Radionuclide station RN43 in Mauritania was established in Nouakchott on 6 November 2006. The historical analysis of the occurrence of relevant radionuclides at RN43 over the past ten years showed that the main contributor was Cs-137, causing several level 3 and level 4. A descriptive statistical analysis of the Cs-137 occurrence was performed and two types of parametric process control methods were applied: the “Shewhart Control Chart” and the “Exponentially Weighted Moving Average (EWMA) Control Chart”. The results of both methods were then analyzed in order to reveal seasonality, possible sources of Cs-137 and correlation with atmospheric phenomena. Speaker: Mr Mohamed Mahmoud Mounja (Mauritania National Authority of Radiation, Safety and Nuclear Security (ARSN), Nouakchott, Mauritania) • 14:20 First observations of environmental 125Xe, 127Xe, and 129mXe 15m Environmental 125Xe, 127Xe, and 129mXe have been observed during testing of a next-generation xenon measurement system, Xenon International. The observations of these three radioxenon isotopes occurred during routine testing at the Xenon International manufacturing facility in Knoxville, Tennessee, USA, and they are believed to be the first observation of these isotopes in environmental samples collected by automated radioxenon systems. The observations are consistent with activation of xenon in air and have been attributed to the High Flux Isotope Reactor (HFIR) located at the Oak Ridge National Laboratory, about 20 km away. The 125Xe, 127Xe, and 129mXe isotopes can be detected in the beta-gamma detector of Xenon International and would interfere with the quantification of the radioxenon isotopes used for nuclear explosion monitoring. The interferences would cause elevated concentration values for the radioxenons of interest in the current analysis methodology. The 125Xe was observed the most often, and it decays to 125I, which can also interfere with radioxenon measurements in the beta-gamma detector. This presentation will describe the observations, production mechanisms, implications for IMS systems and possible mitigation strategies. Speaker: Mr James Ely (Pacific Northwest National Laboratory (PNNL), Richland, WA, USA) • 14:35 Results of the 3rd ATM-Challenge 2019 15m Estimating the radioxenon background based on a multi-input-multi-model ensemble modelling approach at IMS stations having frequent detections was the main goal of the 3rd ATM-Challenge. The Challenge included four selected IMS stations. Participants were invited to calculate contributions to the signal captured in daily samples at CAX17 (St. John’s), DEX33 (Schauinsland/Freiburg), SEX63 (Stockholm) and USX75 (Charlottesville) for up to 6 months. Up to 30 submissions per station from 16 different institutions were finally received. Xe-133 stack emission data with daily temporal resolution for the time period June to November 2014 provided by IRE (Belgium) and CNL (Canada) radiopharmaceutical plants were used. In addition, publicly available emission estimates for nuclear power plants and research reactors as well as annual emissions from other several well-known facilities were also made available to participants. The presentation will summarize the comprehensive results from this study. First, the added value of training an optimized ensemble per station will be discussed. Second, the beneficial impact of including contributions from minor emitters and thus rough emission estimates thereof will be demonstrated. The added value of simulating samples highly influenced by main emitters, i.e. radiopharmaceutical plants, based on actual daily emission data will be exemplified. Speaker: Mr Christian Maurer (Central Institution for Meteorology and Geodynamics (ZAMG), Vienna, Austria) • 14:50 Production of Mo-99 without Use of Uranium 15m NorthStar has embarked on two parallel paths to produce Mo-99 and other medical radioisotopes without use of any uranium material. The first path, which was approved by the US FDA in February 2018, is via neutron capture utilizing a research reactor. In this pathway, NorthStar can use either high-purity natural molybdenum discs or can use target material of enriched molybdenum-98. This pathway has successfully been producing Mo-99 and delivering to the US market for more than two years. The second path, scheduled for production start in late 2022, is the use of electron accelerators to perform photon transmutation using enriched molybdenum-100 target material. In either case, NorthStar’s emissions of gaseous radioisotopes of krypton, iodine or xenon are virtually non-existent. This presentation will provide a review of the production processes and an update to current program status. Speaker: Mr James Harvey (NorthStar Medical Technologies, LLC, Beloit, USA) • 15:05 3-D electrical imaging of mesoscale rock damage patterns from underground chemical explosions 15m Atmospheric gas detection is a primary means for detecting and verifying underground nuclear explosions. Subsurface gas migration is governed by a complex system of unknown variables, including the interaction between geology, explosion-induced stresses and corresponding rock damage patterns that provide primary gas flow pathways. The U.S. is conducting a series of highly instrumented mesoscale experiments that provide an opportunity to better understand the interaction between source strength and location, natural variations in rock competency, explosion-induced rock damage, and gas migration. Rock damage is imaged in 3-D using a novel combination of water injection, draining, heating and drying combined with time-lapse electrical resistivity tomography. Corresponding measurements of induced gas breakthrough times at discrete points in exterior monitoring wells are being used to understand how rock damage is influenced by local geology, and how it influences gas migration away from the source point. Results show that the influence of geologically weak zones on rock damage and gas flow are comparable to the influence of source strength and location. This result has important implications for larger scale underground explosions, and how those explosions interact with geology and alter gas migration flow paths and travel times to the surface. Speaker: Mr Tim Johnson (Pacific Northwest National Laboratory (PNNL), Richland, WA, USA) • 13:31 15:16 T5.3 - Capacity Building, Education, Communication and Public Awareness: Oral session Location 3 (Online) ### Location 3 #### Online • 13:31 Session introduction 4m • 13:35 Simulation exercises and role-plays as effective participatory learning techniques in science diplomacy education 15m MEPhI Science Diplomacy Club (SDC) aims to nurture a new generation of experts who are curious about cross-cutting issues at the interface of science and international relations, who are willing to bridge diplomatic challenges & technical solutions and who are eager to learn more about current challenges including nuclear test ban, non-proliferation and disarmament. The SDC members participate in a wealth of outreach and education activities comprising webinars with experts, presentation contests, summer seminars for pre-university students, Science Diplomacy School, career talks etc. Due to restrictions caused by the COVID-19 pandemic, we had to fully utilize evolving pedagogic methods including distance learning and videoconferencing with a view to holding SDC events in a remote format. We’ll use the occasion of the SnT21 to share our experience of incorporating simulations and role-plays, which are deemed to be one of the most effective participatory learning techniques, into multidisciplinary educational programs. Moreover, we’d like to share our main learnings from The 2020 NPT Review Conference Model which not only highlighted the NPT-CTBT nexus but also showcased the distinct role of the CYG in increasing the visibility of the CTBT. Speaker: Ms Elena Tsyvkunova (National Research Nuclear University MEPhI, Moscow, Russian Federation) • 13:50 Scientist and Diplomats On Site! 15m In the context of the nuclear non-proliferation regime, the On-Site Inspection of the CTBTO play a mayor role for verification. OSI is when Scientists from different fields and diplomats get together with a common aim: “to identify signs from a nuclear explosion”. Only a perfect match between science knowledge and diplomatic skills can assure full success for an OSI. The crucial issue is how to prepare both to be ready to go in to the field and interact properly using a common language and having the same training and motivation. For this to happen diplomats must correctly learn not only about the whole range of technologies involved in an OSI but to experiment in field exercises in order to confirm without any doubt that the data arising from scientific work are reliable, trustworthy and can be used for a proper decision at the political level. Speaker: Gustavo Gonzalez (Ministerio de Relaciones Exteriores de Chile, Chile) • 14:05 Utilization of CTBT-NDC data in geoscience education of Bangladesh 15m Bangladesh, a Comprehensive Test Ban Treaty (CTBT) signatory country since 24 October, 1996, is the 54th state to ratify CTBT on 8 March, 2000. Auxiliary Seismic Station (AS007 BRDH) in Bangladesh, accredited as an internationally certified station, receives the seismic data from International Data Center (IDC) of CTBTO. The seismic station AS007 was established to monitor the activities of nuclear testing through seismic wave propagation in the region. Geoscientists of different academic and professional institutions have been analyzing seismic travel time data from various sources. Accordingly, the objective of the present report is to find out the potential application of regional seismic travel time (RSTT) data in the geoscience researches of Bangladesh. The RSTT data can be applied to analyze this subsurface geological information with the combination of other CTBT seismic stations of the region. Besides seismic data, the IDC has other products, such as radionuclide and noble gas distribution data around the world, hydro-acoustic data for tsunami warning system, etc. Therefore, there is ample scope of introducing IDC products to the geoscience education of Bangladesh. As part of R&D activities through the CTBT-NDC, BAEC is working on this aspect by collaborating with the geology departments of several universities. Speaker: Mr Mohammad Rajib (Bangladesh Atomic Energy Commission, Dhaka, Bangladesh) • 14:35 Knowledge Management in the Context of Comprehensive Nuclear-Test-Ban Treaty (CTBT) Science and Technology 15m In support to the Comprehensive Nuclear-Test-Ban Treaty, the worldwide scientific community - via the CTBT SnT Conferences - has the opportunity to build partnerships and encourage knowledge exchange, allowing the CTBTO to remain at the forefront of the relevant technology for test-ban verification. The SnT Conferences are organized biennially by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organisation (CTBTO). This paper analyses the CTBT SnT topics presented at the Conferences from 2006-2021, capitalizing on scientific and technological applications, trends, innovations and worldwide collaborations. The goal of this work is to provide directions on the knowledge management approach for deep content analysis, strengthening the role of Knowledge Organisation Systems (KOS) as a mechanism and tool for analysing and disseminating content. This research reflects the necessity of creating a KOS-based tool for knowledge recognition and discovery that will encourage communication in a valuable way. Speaker: Ms Marija Sejmenova-Gichevska (Former CTBTO Preparatory Commission, Vienna, Austria) • 14:50 Banning Nuclear Tests: The Role of Public Opinion Research 15m In recent years, there has been a rapid increase in social scientific studies using polling techniques to better understand nuclear issues. Scholars have shown public opinion in numerous countries on subjects such as nuclear proliferation, deterrence posture, and links between civilian and military nuclear technologies. These studies are important contributions for improving decision-maker accountability and more effectively shaping policy to represent public views. We contribute to these discussions by presenting new public opinion data on nuclear explosive testing. The data come from nationally representative surveys we conducted in Belgium, France, Germany, Italy, Japan, the Netherlands, Poland, Sweden, Turkey, the United Kingdom, and the United States. The surveys demonstrate overwhelming public opposition to nuclear testing while also revealing (mis)perceptions about the effects of nuclear test explosions. Taken together, they provide useful information for policy, advocacy, and education aimed at promoting entry-into-force of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Speaker: Mr Stephen Herzog (Yale University, CT, USA) • 15:05 Concluding remarks 10m • 14:30 15:30 The 25th anniversary for opening the CTBT for signature: invited talk on Seismic technology: Invited 25th anniversary talk Location 1 (Onlince) ### Location 1 #### Onlince • 14:30 Challenges and Achievements of Monitoring for Nuclear Test Explosions in the Context of the CTBT 1h Close acquaintance with details of the CTBTO’s International Monitoring System and the International Data Centre can tempt a keynote speaker to present the work as highly complicated, with success coming only via enormous effort. But stepping back from details such as the very size of datastreams received by headquarters in Vienna, and of datasets accumulated after nearly 25 years of operations, it is more important to note the main achievement of the IMS and IDC — namely that the CTBTO draws appropriate attention to events which member States can choose to study in greater or lesser detail. Intense efforts can then be brought to bear on events of particular interest, as deemed necessary by any data user. This presentation will review the basic steps in detecting and analyzing the variety of types of signals generated by nuclear test explosions. It will then present examples of how nuclear test explosions were recorded, first in the earliest days of nuclear weapons development; how these data changed over the forty years leading up to the agreed CTBT text of 1996; and then how data acquired in the present century can be processed using the latest methods applied to broad areas. Speaker: Mr Paul Granston Richards (Lamont-Doherty Earth Observatory of Columbia University, New York, NY, USA) • 15:45 16:15 Series of talks on 25 years of CTBT: Atmospheric Transport Modeling (ATM): Special talk Location 1 (Online) ### Location 1 #### Online • 15:45 Advancements in Atmospheric Transport Modelling (ATM) at the CTBTO PTS during the past two decades and plans for the future. 30m CTBT monitoring for nuclear explosions is based on detection of waveform signals and the related event localization and on detection of traces of treaty-relevant radioisotopes in the atmosphere. However, 25 years ago it was a challenge to obtain a clear link between a seismic event and a series of radionuclide detections. This was changed when the proper Atmospheric Transport Modelling (ATM) system with special postprocessing routines was implemented and the relevant expertise built up. The effectiveness was demonstrated by providing ATM support during events of special interest like the Fukushima accident and the nuclear tests announced by the DPRK. The lessons learnt triggered enhancements. For example, the ATM support during the first DPRK event in 2006 led to the extension of backward trajectories from 6 to 14 days. More recent enhancements include an increase of spatial resolution from 1 degree to 0.5 degree and of time resolution from 3 hours to 1 hour. PTS aims at developing a world-class ATM system and takes all opportunities to validate it against systems from other major ATM centres like participation in multi-model exercises called ATM Challenge. This presentation also addresses the plans for the next years and vision for the longer term. Speaker: Ms Jolanta Kusmierczyk-Michulec (CTBTO Preparatory Commission, Vienna, Austria) • 15:45 16:45 T2.5 - Historical Data from Nuclear Test Monitoring: Oral session Location 2 (Online) ### Location 2 #### Online • 15:45 Session introduction 5m • 15:50 Analysis Of Historical Seismograms Of Central Asia Stations To Precise The Parameters Of Nuclear Tests At Lop Nor Test Site 15m The Lop Nor Test Site is located in Xinjiang Province in the Peoples Republic of China, about 600 km away of Kazakhstan. From 1964-1996, there were 47 nuclear tests, including 3 surface, 19 atmospheric, and 25 underground. During this time, the USSR operated monitoring networks of sensitive seismic stations having both analog and digital instruments. A seismic catalog and bulletin was created using the archived seismograms of Central Asian stations located in Kazakhstan, Kyrgyzstan, and Russia (epicentral distance 700-2500 km). In total, 800 seismograms of 41 explosions were processed. Using satellite imagery, epicenters were précised for all explosions, including atmospheric and small underground tests. The mb, regional mpv and MLV magnitudes, and energy class K were calculated. The waveforms of Lop Nor air and surface explosions were analyzed using microbarograph records from the Talgar Observatory in Kazakhstan. For several small explosions, locations were précised, dynamic parameters of seismic and infrasound records were analyzed, and origin times were calculated for the first time. As a result, the précised catalogue of nuclear explosions conducted at Lop Nor Test Site was compiled. Many of the explosions can be used as Ground Truth events to construct the regional travel-time curves and for stations calibration. Speaker: Ms Inna Sokolova (Institute of Geophysical Research, Almaty, Kazakhstan) • 16:05 Using historical data to improve analysis of nuclear testing 15m Films from historic nuclear testing enable new analysis of the shock propagation and buoyant cloud rise with material entrainment, furthering understanding of the time-evolution of the entrained mass. Many late cloud films were captured from at least two positions, enabling accurate characterization of the cloud development and trajectory. A generalized framework is developed to capture the similarity of nuclear debris cloud formation for detonations with similar scaled heights of burst. The nuclear debris cloud regimes are defined based on debris cloud behavior observed in a dry, dusty environment with loose, easily lofted surface material and can be used to improve dispersion models. As new information on how expected material entrainment and mixing is affected by the surrounding environment becomes available, adjustments to the regime height-of-burst ranges are easy to adopt. Both fast-running fallout codes and higher-fidelity cloud-rise and fallout codes need to be validated against existing test data. We present on the use of historical film to provide many types of data to validate and improve models of late cloud behavior. Combining such data with an understanding of buoyant cloud rise and cloud stabilization informs entrainment including the total mass of entrained materials. Speaker: Ms Stephanie Neuscamman (Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA) • 16:20 Overview on historic atmospheric radionuclide monitoring data associated with nuclear test explosions conducted between 1964 and 1996 15m A literature review is presented on historic atmospheric radionuclide monitoring data that were associated with nuclear test explosions. It covers reports related to tests conducted between 1964 and 1996. Most of these tests occured in the atmosphere but observation of nuclear debris from venting of underground nuclear tests were also found.The review is limited to off-site monitoring and many observations were done at large distances including several tests that were detected on multiple locations on the same hemisphere. This data set could be of value for validating methods based on atmospheric transport simulations with the objective of identifying the source of an event that is of relevance for atmospheric radioactivity monitoring for the Comprehensive-Nuclear-Test Ban Treaty. Speaker: Mr Martin B. Kalinowski (CTBTO Preparatory Commission, Vienna, Austria) • 16:35 Concluding remarks 10m • 15:45 17:15 T3.6 - Artificial Intelligence and Machine Learning: Oral session Location 3 (Online) ### Location 3 #### Online • 15:45 Session introduction 5m • 15:50 Beta-Gamma coincidence radioxenon spectra classification using the convolution neural network (CNN) technique 15m In this study, using a machine learning method, in particular, a deep learning approach, we propose for the first time a model of Beta-Gamma coincidence radioxenon spectra classification. Specifically, by means of real data from the noble gas system in Charlottesville (USX75) as part of the International Monitoring System (IMS) operated by CTBTO between 2012 and 2019, we apply the convolution neural network (CNN) technique based on the absolute concentration of each radioxenon isotope. The results show that without utilizing background spectra, interference corrections, and without determining the activity concentration of each isotope, the automatic classification can be carried out with high accuracy. This implies that categorization through deep learning does not require the knowledge of screening threshold values that are applied for sample categorization after applying the Net Count Calculation (NCC) analysis method used currently by the International Data Centre (IDC) of the CTBTO. Our results support that by synthesizing nuclear engineering and deep learning disciplines, experts can accelerate and optimize the review process of background and CTBT-relevant samples by an average accuracy of 92% and 98% respectively. Speaker: Ms Sepideh A. Azimi (Amirkabir University of Technology (AUT), Tehran, Iran) • 16:05 Markov Chain Monte Carlo Estimate of Origin Error for Seismic, Hydroacoustic, Infrasound Events in NET-VISA 15m NET-VISA is a Physics-Based Generative Model of global scale seismology. The model includes a description of the generation of events which include under-water and atmospheric events, the propagation of waveform energy from the events in multiple phases, and the detection or mis-detection of these phases at the network of stations maintained by the International Monitoring System (IMS) as well as a model of noise processes at these stations. The model and its associated inference algorithm has been deployed by the International Data Center (IDC) to generate a bulletin of events known as VSEL3. This bulletin is currently being used by the analysts to generate the LEB bulletin and in future it is planned to replace the current GA-based SEL3 bulletin with VSEL3. The current version of the inference algorithm relies on the existing IDC libraries to compute the error/coverage ellipse of events. In this work we have added a new module to directly use the NET-VISA model to estimate the 90% confidence ellipse. We describe the details of the Markov Chain Monte Carlo (MCMC) estimation and demonstrate on a study of ground truth events from the International Seismological Center (ISC) that the new confidence ellipses are more accurate. Speaker: Mr Nimar Arora (Bayesian Logic, CA, USA) • 16:20 Emulation of seismic-phase travel times using the Deep Learning Travel Time (DeLTTa) method 15m Deep Learning Travel Time (DeLTTa) is a deep-learning method and computer code for emulating seismic-phase travel times that are based on a 3-dimensional (3D) Earth model. Greater accuracy of travel time predictions using a 3D Earth model are known to reduce the bias of event location estimates and improve the process of associating detections to events. However, practical use of 3D models is challenged by slow computational speed and the unwieldiness of pre-computed lookup tables. DeLTTa trains a deep-learning network using pre-computed travel times, resulting in a compact and computationally fast way to approximate travel times based on a 3D Earth model. DeLTTa is trained using approximately 850 million P-wave travel times based on the LLNL-G3D-JPS model from randomly sampled event locations to 10,393 global seismic stations. After training, the machine-learning computer code is approximately 10 Mbytes in size and travel times are computed in approximately ten micro-seconds on a single CPU. Currently achieved prediction accuracy is approximately ½ second at the 2-sigma level, which is similar to the inherent accuracy of the 3-D model. With additional development, DeLTTa will enable easy use of 3-D models in routine seismological processing and analysis. Speaker: Mr Stephen Myers (Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA) • 16:35 Identification of repeating seismic events using non-linear dimensionality reduction 15m In this work, we develop an algorithm for automatic identification of repeating seismic events such as aftershocks and mine explosions. Identification of such events will help to improve the quality of automatic bulletins and to lighten the analysts’ burden. The algorithm constructs a low-dimensional representation of the examined data by using a variant of a non-linear dimensionality reduction algorithm named diffusion maps. The proposed methods begin with a pre-processing stage in which a time–frequency representation is extracted from each seismogram while capturing common properties of seismic events and overcoming magnitude differences. Then diffusion maps are used in order to construct a low-dimensional model of the original data. This enables to split the data into one cluster that contains the repeating events and another cluster that holds of the other processed waveforms, which are not related to the examined events of interest. The algorithm’s performance is demonstrated on several seismic data sets that were recorded at IMS stations. In particular, at the IMS station EIL we identify arrivals that were caused by the blasts at the nearby Eshidiya mine in Jordan. Identification and masking of such arrivals should reduce the number of false associations in the automatic bulletins. Speaker: Mr Yuri Bregman (Soreq Nuclear Research Center, Yavne, Israel) • 16:50 Using machine learning to detect and characterize long-range infrasound signals from high explosives 15m The International Monitoring System (IMS) infrasound network is well positioned to record atmospheric nuclear explosions, but algorithmically classifying and characterizing these events is challenging. Difficulties stem from the variable and dynamic atmosphere that modulates acoustic transients at regional to global distances. Machine learning (ML) is well suited to classify infrasound activity but generally requires large training datasets. However, data from the relatively few large chemical explosions and sparse global infrasound network are insufficient to train a ML model given how complex and dynamic the atmosphere is at global scales. Instead, we propose a physics-based data augmentation method to produce an entirely synthetic training dataset. Realistic source time functions are generated and propagated through modeled atmospheres out to several hundred kilometers, thus producing a catalog of synthetic events. These data are then used to train a time convolutional neural network (TCN) that classifies explosions and background noise. We show the TCN not only identifies modeled events but is also effective at detecting and characterizing real world explosive transients, including those from the Humming Roadrunner experiments. This work was supported by the Nuclear Arms Control Technology (NACT) Program at Defense Threat Reduction Agency (DTRA). Approved for public release; Distribution is unlimited. Speaker: Mr Alex Witsil (University of Alaska Fairbanks, Fairbanks, AK, USA) • 17:05 Concluding remarks 10m • 16:15 17:15 The 25th anniversary for opening the CTBT for signature: invited talk on Radionuclide technologies: Invited 25th anniversary talk Location 1 (Online) ### Location 1 #### Online • 16:15 The IMS radionuclide network- a unique machine not yet fully exploited 1h The IMS Network of 80 particulate and 40 radioxenon measurement systems is one of its kind in several ways. The global coverage combined with high time resolution contributes to a unique, steadily growing data set available to all CTBT member states. The requirements of the verification regime, formulated more than 25 years ago, prompted the development of new measurement technologies, such as automated particulate samplers and radioxenon systems. The area of radioxenon detection in particular got a considerable boost, and still remains a very active research area. However, I believe we just got started on the journey towards an even more effective verification regime. Besides describing the development of the past 25 years, I will try to look into the future and discuss a few topics that I believe will be important in the years to come. The development has so far mainly been focused on the individual measurement systems, achieving high measurement sensitivity with high reliability. Less effort has been put on optimizing the network as a whole, with the goal to maximize the combined capability to detect, locate and characterize release sources. I am convinced that by viewing the network as a single measurement system, many improvements still can be made, both with respect to measurements as well as data analysis. Another important remaining task is to identify as many background sources as possible. There are many unexplained detections in the network, and understanding the causes for these is absolutely crucial to the CTBT verification regime. Speaker: Mr Anders Ringbom (Swedish Defence Research Agency (FOI),Stockholm, Sweden) • 16:45 18:30 T1.2 - The Solid Earth and its Structure: Oral session Location 2 (Online) ### Location 2 #### Online • 16:45 Session introduction 5m • 16:50 Monitoring sub-seafloor deformation in plate subduction zone 15m Fault rupture in a subduction zone often causes devastating earthquake and tsunami hazards. Therefore, understanding a slip behavior along the fault is a crucial scientific topic and a deeply socially relevant problem. To understand the slip behavior along the fault, there are two kinds of essential geophysical datasets. One is seafloor displacement as a surface response of a fault slip, and the other is the sub-seafloor structure, which is needed to transform a surface displacement to a fault displacement. Recent studies reveal that surface displacements due to fault slips show a wide-spectrum of their frequency, from a regular earthquake (~10 Hz) to a long-term slow slip (~months). To monitor the entire spectrum of the fault slip, monitoring the displacement with a seismo-geodetic band in real-time continuously is necessary. And also, to transform the displacement to the slip along the fault, it is essential to know a realistic structure of a medium (lithospheric structure) in the subduction zone. JAMSTEC is conducting an integrated geophysical project to establish a real-time continuous seafloor geodetic network in the Nankai Trough, Japan, and construct a three-dimensional structural model using seismic data. We will present an outline and recent results of the project in this presentation. Speaker: Mr Shuichi Kodaira (Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa, Japan) • 17:05 Velocity structure of the uppermost mantle beneath the tanzanian craton and the surrounding proterozoic mobile belts from pn tomography 15m The uppermost mantle structure beneath East Africa is investigated by inverting the Pn traveltimes to obtain a model of P wave velocities. The previous Pn tomography models of the region have been expanded. A total of 2870 new Pn travel time measurements of local and regional earthquakes have been made and modeled, improving the resolution of the uppermost mantle velocity structure across much of East Africa. The new Pn tomography model shows variations in uppermost mantle velocities across the region which can be used to understand the size of the Tanzania Craton and the differences between the Eastern and Western branches of the East African Rift System (EARS). Results reveal fast Pn velocities beneath the Tanzania Craton, the extension of these fast velocities beneath the Mozambique Belt to the east of the craton, the Kibaran Belt west of the craton, and beneath the northern half of the Ubendian Belt to the southwest of the craton. In addition, the fast Pn velocities beneath the Western Branch everywhere contrast with the slow Pn velocities of 7.5-7.8 km/s beneath the Eastern Branch in Kenya, showing that the upper mantle beneath the Eastern Branch has been altered much more than beneath the Western Branch. Speaker: Ms Nada El Tahir (University of Khartoum, Sudan) • 17:20 A crustal P-wave velocity model for Israel to improve IMS capabilities in the Middle East 15m The Israeli National Data Center is responsible for monitoring and characterising the seismicity of the Eastern Mediterranean region. The accuracy of seismic locations is mostly affected by the velocity model used, and no clear picture of the variations in seismic velocities in Israel has emerged in the recent years. We gathered a large dataset of seismic travel times recorded in Israel and nearby countries. After quality control and joint relocation of over 30,000 natural and man-made seismic events, we produced a revised dataset of more than 500,000 arrivals. From this dataset, we inverted Pg and Pn travel times for a crustal velocity model of the area using the FMTOMO tomographic inversion package. In order to do this, we put together a 3-D starting model that consists of an ensemble of 1-D velocity profiles for the various tectonic settings observed in the region. We present images extracted from this model, as well as corresponding synthetic resolution tests to assess the quality of our results. This high-resolution model is to be integrated into the Regional Seismic Travel Time model and procedure in order to enhance the CTBT’s International Monitoring System capabilities in the Middle East. Speaker: Mr Lewis Schardong (Tel-Aviv University, Israel) • 17:35 3D Dynamic Earthquake Rupture Simulations In The Sea Of Marmara 15m The center of the Sea of Marmara, the region between the locations of 1912 Mürefte and 1999 Izmit M_w7.4 earthquakes, is prone to creating a large earthquake. The main objective of our study is to determine 3D dynamic earthquake rupture scenarios, considering non-planar and heterogeneous stress distribution in the Sea of Marmara. In this study, it is the first time that we attempt to generate realistic earthquake scenarios by putting constrains on initial stress on the fault using regional stress from earthquake focal mechanisms, in addition to stress release during past earthquakes and strain accumulation during interseismic period using geodetical measurements on slip-rate and locking depth at various segments. We use 3D Finite Element Method (PyLith) for dynamic earthquake simulations and tetragonal mesh for better smoothing at the fault bends, which allows us to implement nonplanar fault geometry and initial stress heterogeneity using slip-weakening friction law. We place constraints on initial shear stress from geodetic and seismic studies of locking depth and interseismic strain accumulation. We consider more than a hundred rupture scenarios and calculate slip distribution, rupture velocity and moment magnitude in addition to slip-rate and traction on the fault surface, and displacement and velocity on the ground surface. Speaker: Ms Yasemin Korkusuz Öztürk (Bogazici University, Istanbul, Turkey) • 17:50 Teleseismic depth determination, techniques and uncertainties : an Himalayan case study 15m Accurate estimates of the depth of seismic events allow determining whether they are associated to a given tectonic structure. It is also a good discriminator between earthquakes and explosions. However, automatic depth determination at teleseismic distance remains a challenge: the depth phases (pP, sP), reflected on the free surface, are sometime difficult to pick in the teleseismic signal. This is particularly true when the events are intermediate magnitudes (Mw<5), and fall at shallow depths in complex tectonic environments. To overcome that challenge, we implement two teleseismic depth estimation methods : (1) a cepstral analysis allowing to extract the pP-sP reflected waves in a the P-coda from their phase's similarity with the direct P wave and (2) an envelope stacking procedure aiming to highlight these secondary arrivals from their energetical contents. These two complementary methods allow improving signal over noise ratios and automatically identifying coherent depth phases among the thousands of teleseismic stations and arrays available from global teleseismic networks, including those of the International Monitoring System monitored by CTBTO. We confront our results to a set of well determined regional depths determined from a dense temporary network deployed in the Nepalese Himalayas, a region of high-topography and relatively shallow seismicity. Speaker: Ms Marine Laporte (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France) • 18:05 P-wave arrival-time tomography of the Middle East 15m High-resolution tomographic images of the MiddleEastern region are essential to accurately locate ground motion events during nuclear monitoring programs. The purpose of this study is to retrieve detailed models down to lowermantle beneath the Middle Eastern region using a set of reliable regionally observed teleseismic P arrival times from the ISC-EHB bulletin (Engdahl et al., 1998). Our current inversion results are consistent with the previous regional tomographic studies. In checkerboard tests of cell dimension as low as$\sim2.4^{\circ}$($\sim$280 km at surface) are well recovered down to a 1000 km depth beneath the Anatolian plateau where we currently have the densest coverage with ISC data. The Caucasus region and northern parts of the Iranian plateau shows good recovery of$\pm4\%$Vp perturbation amplitudes at depths$\sim$70 – 135 km. There is fair recovery for a minimum of$\sim2.4^{\circ}\$ cell size beneath the Iranian Plateau, Zagros mountain region, Persian gulf, and northeast Iraq. We are able to further improve coverage especially down to lithospheric depths within the Arabian peninsula using first arrival times measured from waveform data collected from regional networks.
The ultimate goal is to perform full-waveform inversion of the region constrained by the constructed P-wave model.

Speaker: Ms Ebru Bozdag (Colorado School of Mines, CO, USA)
• 18:20
Concluding remarks 10m
• 17:15 18:45
Panel discussion on Innovation affecting CTBT – pertinent to IMS monitoring system (sensors): Panel discussion Location 1 (Online)

### Location 1

#### Online

• 17:15
Innovation affecting CTBT: pertinent to IMS monitoring system (sensors) 1h 30m

The CTBT IMS employs four monitoring technologies: seismology, infrasound, hydroacoustics and radionuclide (both particulate and noble gas). It is vital that the PTS stays abreast of new developments related to all sensor types to maintain its high-performance level, and network sustainability, in order to safeguard and improve the Treaty Verification capability. This panel will discuss new generation sensors that may already be available, and innovative efforts for future developments. Potential areas of discussion are networks of infrasound sensors, combination of rotational and directional seismic sensors, modular design hydroacoustic hydrophone stations, SMART underwater cables and sensors, fibre-optic seismometers and hydrophones, improved concepts for particulate radionuclide stations, new generation of noble gas stations.

Speaker: Ms Nurcan Meral Ozel (CTBTO Preparatory Commission, Vienna, Austria)
• 17:16 18:16
Event 2 - Resilience of the CTBT monitoring regime: Event Location 3 (Online)

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#### Online

• 17:16
Event 2 on Resilience of the CTBT monitoring regime, including lessons learned from the COVID-19 pandemic crisis 1h

The COVID-19 pandemic is a major topic of interest for the SnT2021. The global nature of it produced a resilience test for many, and in particular for a global monitoring system, such as the CTBTO’s, that relies on continuous data gathering, transmission and analysis. The objective of this series of two events is to provide the audience with pertinent case histories and lessons learned from IMS stations e.g. during O&M activities, station upgrades or logistics challenges, faced by the station operators and PTS during the restrictions imposed by COVID-19.
Topics presented in Event 3 are (i) the basis on which INPRES, Argentina, was able to continue providing its essential services during the COVID-19 pandemic and how the face-to-face work and the use of Software for Telework and new work standards affected some PLCA/PS01 station metrics, (ii) how the COVID-19 restrictions affected the operation and maintenance of the IMS infrasound and radionuclide stations operated in Argentina by ARN, (iii) the technical and logistical challenges faced and overcome by INOCAR, Ecuador, while operating and maintaining IS20 and RN24 in Galapagos during the COVID-19 pandemic. (iv) A demonstration of how technical, environmental, logistical and administrative challenges faced at IS35 infrasound station, Namibia, in conjunction with COVID-19 lockdowns, were overcome to bring the station back to life and return it to mission capability, and (v) examples presented by CTBTO IDC/OPS of restrictions imposed by the COVID-19 pandemic that affected the resolution of operational issues with impact on timely data availability/data quality, together with contingency measures employed.

Speaker: Ms Stefka Stefanova (CTBTO Preparatory Commission, Vienna, Austria)
• Wednesday, 30 June
• 09:30 12:30
e-poster session - day 2: e-poster session - Theme 2 (T2.1, T2.2, T2.3, T2.4 and T2.5) Online

#### Online

E-poster session for:
- T2.1
- T2.2
- T2.3
- T2.4
- T2.5

• 10:59 12:14
T4.5 - Resilience of the CTBT Monitoring Regime, including Lessons Learned from the COVID-19 Pandemic: Oral session Location 1 (Online)

### Location 1

#### Online

• 10:59
Session introduction 6m
• 11:05
Performance of the Global Seismographic Network (GSN) During COVID: Challenges and Opportunities 15m

We review the impact of the COVID-19 pandemic on Global Seismographic Network (GSN) operations. GSN stations, of which 50 also serve as IMS auxiliary Seismic Stations, have been designed to operate autonomously with very little operator intervention for long periods of time. These design goals have been strenuously tested with the advent of the COVID-19 pandemic, as travel by both local station operators and field engineers has been severely curtailed. We present examples of adaptive maintenance and repair strategies and the impact these have had on data return. Station downtimes are often limited by pre-positioned spares that may be easily swapped for damaged elements. Despite COVID-related impacts, the overall network uptime since January 2020 at 87%, while down from 88.7% in 2019, continues to exceed our funding agencies’ data availability metric of 85%. Planned equipment upgrades and preventative maintenance have been postponed, which may affect future system reliability. COVID and the constraints that the disease places on travel have led to increased use of tele-consulting by remote field engineers with local operators, which we anticipate will lead to enhanced local capabilities and improved overall efficiencies.

Speaker: Ms Katrin Hafner (Incorporated Research Institutions for Seismology (IRIS), Washington, USA)
• 11:20
Seismic Monitoring in Canada During COVID 15m

We describe the standard pre-COVID mode of operations for the Canadian National
Seismograph Network, a large continental-scale monitoring network, and for the associated IMS stations in Canada. We examine how the operational posture has evolve and then discuss the manners in which the posture was found suitable and unsuitable to respond to the challenges and constraints of the COVID-19 situation in Canada. We find that many of the design and operations decisions that have been taken over the last several decades for seismic monitoring operations in Canada, driven largely by considerations of resilience and cost-effectiveness, and further refined after the lessons-learned of the H1N1 pandemic, resulted in a system that continued to function effectively under pandemic lockdown conditions. Specific challenges and lessons learned during the first annual cycle of the pandemic are noted.

• 11:35
Maintaining Operational Capability During COVID-19 15m

General Dynamics Mission Systems (GDMS) overcame new challenges and implemented innovative strategies to maintain International Monitoring System (IMS) minimum requirements during the COVID-19 pandemic. GDMS focused on five areas: on-site spares, enhanced training material, refined quality assurance processes, development of remote preventive maintenance, and the health and wellbeing of team members, in order to maintain the resilience of the CTBT monitoring regime.
GDMS launched remote training curricula to further local operator maintenance capabilities and implemented video procedures to enhance troubleshooting effectiveness. These remote training opportunities provided GDMS with valuable information regarding the nuances of local conditions and environments in response to the pandemic. GDMS tailored preventive maintenance plans to identify station specific needs to safeguard stations from critical failures. Efforts to secure team member safety and wellbeing in their daily operation through shift-scheduling, instant- and video-focused communication methods, and regular seminars and workshops effectively advanced inter-team knowledge and created a more efficient work structure while maintaining health and safety requirements.
These measures, while critical in the midst of the COVID-19 pandemic, revealed many lessons learned regarding efficiency, communication, and innovation. GDMS looks forward to continuing implementation after the pandemic in daily operation and unforeseen circumstances.

Speaker: Ms Noor Al-Alami (General Dynamics Mission Systems (GDMS), Chantilly, VA, USA)
• 11:50
Operation of the IMS network during the COVID-19 Pandemic - Challenges and Solutions 15m

The CTBTO Provisional Technical Secretariat is responsible for supervision and coordination of the IMS network operations, and for providing assistance to assure proper functioning of IMS facilities. Station Operators are responsible for the operation of the IMS facilities, in accordance with the Operational Manuals, while complying with facility specific contracts, agreements and arrangements. The global response to the COVID-19 pandemic has brought about numerous unprecedented challenges for the operation of the IMS network. Station Operators have faced challenges in accessing and operating their facilities during lockdown phases, and logistical problems such as spare parts shipments have increased during elongated periods with severe travel limitations.

This presentation will detail on those challenges, including difficulties with visits to IMS stations, RN QA/QC sample shipments, scheduled calibrations, and troubleshooting of unstable communication links. Through several monitoring tools and the COPC Operations Centre, the PTS carries out comprehensive analyses of the network to provide practical solutions to Station Operators. Continuous communication, availability and flexibility in supporting Station Operators are the key to manage such critical conditions. Further enhancements of PTS monitoring tools are under development to support IMS Station Operators in their intent to improve data availability, data quality and data surety.

Speaker: Mr Thomas Ludwig Hoffmann (CTBTO Preparatory Commission, Vienna, Austria)
• 12:05
Concluding remarks 9m
• 11:00 12:45
T3.5 - Data Analysis Algorithms: Oral session Location 2 (Online)

### Location 2

#### Online

• 11:00
Session introduction 5m
• 11:05
An updated prediction of xenon background levels at IMS locations 15m

The International Monitoring System (IMS) was designed based on planned sensitivity estimates, such as radionuclide (RN) system minimum detectable concentration (MDC), but without knowledge of background levels. Recent background simulations and atmospheric transport modeling calculations show that for most of the Earth, using MDC values is still reasonable. However, for a number of locations, background xenon concentrations are frequently larger than the measurement equipment limitations and impose mild to severe limitations on the size of anomalous signal that can be discerned. The authors have calculated maps and statistical estimators of network capability for computed xenon background levels, using a threshold balanced between the MDC and background intensity and variability. Despite these limitations, xenon continues to be a very worthwhile monitoring method.

Speaker: Mr Paul Eslinger (Pacific Northwest National Laboratory (PNNL), Richland, WA, USA)
• 11:20
Radioxenon isotopic ratios from activation of stable xenon in releases from nuclear facilities in relation to fission sources visualized in multi-isotope-ratio plots 15m

Evidence has shown that besides radioxenon from fission, release of activation-generated radioxenon can occasionally be observed at noble gas systems of the International Monitoring System (IMS). The literature appears to show conflicting results for the isotopic ratios from activation of stable xenon in the releases from nuclear research reactors (NRRs). This study uses ORIGEN simulations to investigate various scenarios of generating radioxenon from activation. Different neutron spectra and activation of air as well as gas dissolved in the water are studied. The main goal is to test the hypothesis that the isotopic activity ratios can be used as a discriminator for activation or fission being the dominating source of radioxenon releases from NRRs or other nuclear facilities. This is important because any source of activated xenon that can be observed in IMS samples may release other activation products as well 125Xe, 127Xe and 129mXe which interfere with the beta-gamma spectroscopy analysis methods which are applied by the International Data Centre (IDC). This is an important scientific foundation to decide whether interference corrections for these non-traditional radioxenon isotopes need to be introduced to the operational software.

Speaker: Ms Pouneh Tayyebi (Iran Nuclear Regulatory Authority, Tehran, Iran)
• 11:35
Novel IDC software applications for Radionuclide data analysis 15m

The CTBTO International Data Centre (IDC) initiated the development of novel software applications for modernizing automatic processing and interactive analysis of radionuclide data from the International Monitoring System (IMS).
The ongoing projects aim at completing the migration to open source license free software, unifying the processing tools for particulates and noble gas, integrating new technologies and analysis methods as well as enhancing the IDC products and dissemination tools for National Data Centers (NDCs).
The presentation will provide updated status and future plans on ongoing projects:
(a) iNtegrated Software Platform for Interactive Radionuclide rEview (iNSPIRE),
(c) Geant4 based RAdioNuclide Detector Simulation (GRANDSim) and
(d) new web based application (RNToolkit).

Speaker: Mr Abdelhakim Gheddou (CTBTO Preparatory Commission, Vienna, Austria)
• 11:50
Transition RN to SHI 5m
• 11:55
Multicomponent seismic arrays: demonstrating their potential for improved event detection and characterisation 15m

IMS seismic arrays are predominantly formed using multiple vertical sensors with a single three-component (3-C) seismometer co-located at one site. The deployment of fully 3-C seismic arrays, such as ARCES (PS28) and SPITS (AS72), offers the possibility to take additional advantage of the coherency on the horizontal components. For the case of S-phases, this has the potential to significantly improve their detection and characterization. Despite this, 3-C arrays are currently poorly exploited in automatic phase detection and classification algorithms.

Using events from the 2020 NORSAR regional reviewed bulletin and based on data from the ARCES and SPITS arrays, our work focuses on demonstrating the benefits of using all three components for array processing. We use the PMCC (Progressive Multi-Channel Correlation) algorithm to initially process each individual component, merging the results to form a multi-component phase detection, from which a Kurtosis phase picker is applied. For a second, more computationally intensive technique, we use all three components to rotate our data into a ray-coordinate system for a predefined set of azimuth and slowness values. Each component of the rotated data are then processed, with the resulting detections compared to both the vertical-only results and the PMCC multi-component technique

Speaker: Ms Claire Labonne (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France )
• 12:10
Regional waveform-correlation detection and location, for seismic events in and near Mongolia 15m

We have engaged in broad-area regional monitoring for Mongolia and nearby regions, applying cross-correlation to long time windows for Lg-waves. For 2012 to 2016, using 4777 templates from a longer time-period, detections were made on searches of continuous data for a sparse network of IMS array stations, plus six long-running three-component open stations. Many candidate events were detected, for which there were too few stations in the detection network to perform locations. Fortunately a temporary PASSCAL network with many stations had been deployed in the region, which overlapped with the time period of our study. Adding windowed data from that network, based on expected arrival times for Lg-waves, we measured differential travel times to make location estimates. We have obtained pair-wise locations for 35,096 events in the detected catalog (4.7 million pairs of events). Location results are similar to those obtained in a previous study for all of China (Schaff et al, BSSA, June 2018) with average residuals of 0.0164 s; and 95% confidence ellipses with average 157 m semi-major axes. 93% of the pairs are less than 1 km apart. We are computing locations within large clusters of over 1000 events in several areas.

Speaker: Mr David P. Schaff (Lamont-Doherty Earth Observatory of Columbia University, New York, NY, USA)
• 12:25
Comparing three-dimensional velocity models for seismic location accuracy using a consistent travel time framework 15m

Location algorithms have relied on simple, one-dimensional (1D) velocity models for fast, seismic event locations. The fast-computational speed of these models made them the preferred type of velocity model for operational needs. Higher-dimensional (2D-3D) seismic velocity models are becoming readily available and provide more accurate event locations over 1D models. The computational requirements of these 2D-3D models tend to make their operational use prohibitive. 1D are generally used as travel-time lookup tables, one for each seismic phase, with travel-times pre-calculated for event distance and depth, that are extr fast to use. Comparing location accuracy for 2D-3D seismic velocity models tends to be problematic as each model is determined using different ray-tracing algorithms. Attempting to use a different algorithm than used to develop a model usually results in poor travel-time prediction. We will demonstrate the current/updated ability to quickly create travel-time correction surfaces using an open-source framework (PCalc+GeoTess, www.sandia.gov/geotess) that easily stores 3D travel-time data. This framework overcomes the ray-tracing algorithm hurdle because the lookup tables can be generated using the exact ray-tracing algorithm that is preferred for the model. Having a common travel-time framework for a location algorithm allows individual velocity models to be compared in a fair, consistent manner.

Speaker: Mr Michael L. Begnaud (Los Alamos National Laboratory (LANL), Los Alamos, NM, USA)
• 12:40
Concluding remarks 5m
• 11:30 12:30
The 25th anniversary for opening the CTBT for signature: invited talk on Hydro-acoustic technology: Invited 25th anniversary talk Location 1 (Online)

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• 11:30
The CTBT Hydroacoustic Network at 25 years 1h

This presentation addresses the history of the CTBT hydroacoustic network, from its broad definition during negotiations of the Treaty through its establishment over the 25 years following the opening for signature of the CTBT.
Hydroacoustic network discussions during the negotiation of the CTBT will be addressed, including rationale for decisions that were made. The network concept was further solidified during the early years of the CTBTO, leading to the first Hydroacoustic Operational Manual.
The early work on establishing the hydrophone stations required innovative thinking to establish stations that would work as specified, be highly reliable, and be as maintainable as possible.
The progressive build-up of the hydroacoustic network has led to its current status of being the only fully certified technology in the CTBT network. It is a unique global observatory which is providing data not just for CTBT purposes, but also data for various civil and scientific uses. The underwater location of major elements of the hydrophone stations causes difficulties in sustaining them. Underwater repairs/replacement are very expensive, complex, and time consuming which provides a challenge in both installing highly reliable equipment and dealing with failure when it does occur.

Speaker: Mr Martin Lawrence (Sydney Institute of Marine Science, Sydney, Australia)
• 13:15 14:15
Panel discussion on Resilience of the CTBT monitoring regime, including Lessons learned from the COVID-19 pandemic crisis: Panel discussion Location 1 (Online)

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• 13:15
Lessons learned from the COVID-19 pandemic crisis as a Resilience of the CTBT monitoring regime 1h

The global pandemic of the past year has put a substantial amount of strain on many systems, with the CTBT monitoring regime being no exception. At the same time, the crisis has proved to be a significant and valuable resilience test. This panel explores the impacts of the COVID-19 pandemic on the establishment, operation, maintenance and sustainment of the IMS monitoring network, and the measures that were taken to ensure continued data availability and timely delivery of monitoring products. Lessons learned, possible follow-up steps and measures to assure a sustainable and resilient monitoring regime into the future are also discussed, with perspectives provided from Member States Station Operators, National Data Centres (NDCs) and the point of view of organizations with operational experiences gathered from the field during this period of time.

Speaker: Ms Stefka Stefanova (CTBTO Preparatory Commission, Vienna, Austria)
• 13:30 14:45
T2.2 - Challenges of On-Site Inspection: Oral session Location 2 (Online)

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• 13:30
Session introduction 5m
• 13:35
Potential Application of Unmanned Aerial Vehicles for On-Site Inspection 15m

In 2018 the 51st Session of Working Group B (WGB-51) of the Provisional Technical Secretariat of the Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) noted potential applicability of remotely operated vehicles (ROVs) for OSI purposes, but their practical use raises several serious issues that WGB should discuss at its future sessions.
Implementation of OSI missions with application of unmanned aerial vehicles (UAV) for aerial multispectral imaging, gamma-radiation monitoring as well as geomagnetic field mapping specified in paragraph 69 Part II of the Protocol would be technically feasible. But at the same it will be necessary to consider legal, technical and organizational issues relating to UAV use for OSI purposes.
Based on the example of mostly geomagnetic field mapping technique this paper examines technical capability of UAV application for OSI purposes, its consistency with the Treaty provisions and potential approaches for their resolution.

Speaker: Mr Dmitrii Sagaradze (All-Russian Scientific Research Institute Of Technical Physics (VNIITF), Russian Federation)
• 13:50
Provisioning and updating distributed software systems in network-isolated environments 15m

Security constraints of an On-Site Inspection dictate air-gapped isolation of networks, introducing challenges for the reliable provisioning and updating of distributed mission-critical software systems employed during an OSI. Further goals include process transparency and operational robustness, while accommodating domain-specific requirements. To this end, we propose a technical framework addressing the software configuration update in network-isolated environments. Within our comprehensive framework, dependencies are resolved using satisfiability modulo theories, ensuring correctness in terms of version compatibility. The end-to-end system facilitates the update and reconfiguration of isolated on-site systems, while being compatible with container-based software component management as used in practice. We demonstrate the framework over a case study representing a typical scenario.

Speaker: Mr Oleksandr Shabelnyk (Technische Universität, Vienna, Austria)
• 14:05
Geophysical modeling mathematical software 15m

The importance of mathematical modeling lies in the implementation of complex calculations and analysis of results using known computational methods. Mathematical modeling provides a qualitative and quantitative prediction of the behavior of an object or a system in cases their study is difficult in reality.
The aim of this work was to create mathematical software that allows modeling geophysical background fields and their anomalies for the purposes of the CTBT On-site Inspection. The simulation results helped to better understand and describe changes of studied values for the search for the epicentral zone of the geophysical anomaly. And the use of data fusion method increased the efficiency of the algorithms performed to identify the location of the geophysical anomaly.
To achieve this goal, the following tasks were solved:
• analysis of the CTBTO verification regime;
• problem statement for mathematical modeling of gravity, magnetic, radionuclide anomalies;
• development of algorithms for solving formalized models;
• analysis of the feasibility of using data fusion for the selected methods;
• development of method and algorithm for data fusion;
• development of mathematical software.
The result of the research work was the created mathematical software that allows modeling background geophysical fields and their anomalies.

Speaker: Ms Sofya Bukhalina (National Research Nuclear University MEPhI, Moscow, Russian Federation)
• 14:20
Electrical Resistivity Tomography Geophysical Technique for Mapping Base Metal and Gold Mineralization Potential in Iperindo, Ilesha Schist Belt, Southwestern Nigeria 15m

Electrical Resistivity Tomography (ERT) geophysical technique has been applied in this study to evaluate the base metal and gold mineralization potential of Iperindo in Ilesha Schist Belt, southwestern Nigeria, where commercial exploitation capable of generating revenue and employment for the inhabitants has been challenged by lack of /inadequate subsurface geological/geophysical information. The filtered and inverted electrical resistivity data acquired by occupying five 336 m long E – W trending profiles, established 10 m apart from each other, delineate isolated near-surface but thick (> 30 m) low resistivity zones, especially at the eastern and western ends of the study area. Some of the delineated low resistivity zones (3 – 200 𝛀m) present sharp vertical edges, likely created by vertical faults that flank the zones on both sides. The low resistivity signatures of these zones could be attributed to the occurrence of conductive minerals such as gold and associated base metals which probably exist in pegmatitic veins within the zones. The resistivity/conductivity distribution generated by ERT mapping of spatial distribution of base metal within the subsurface clearly demonstrates the earth imaging strength of geophysics techniques which are applicable for on-site inspection and test ban verification.

Speaker: Mr Olawale Osinowo (University of Ibadan, Nigeria)
• 14:35
Concluding remarks 10m
• 13:31 14:31
Educational Initiative for Young Professionals with Technical Background: International Gender Champions - CTBTO Youth Group
• 13:31
Gender Champions and Youth - Collaboration for Successful Outcomes 1h

(Description to be provided soon)

• 14:15 14:45
Series of talks on 25 years of CTBT: Data analysis: Special talk Location 1 (Online)

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• 14:15
Machine learning prospects for automatic SHI processing 30m

At the time of the opening of the Comprehensive Nuclear-Test-Ban Treaty for signature in 1996, machine learning was a relatively young but already established data analysis method in some fields. However, in seismology it had not reached a sufficient level of maturity to be considered for Treaty monitoring purposes. Furthermore, machine learning requires computational capabilities that exceeded the capabilities of most data centres at that time. Automatic processing at the International Data Centre (IDC) followed the standard, tested and established processing methods benefitting from knowledge that the seismological community had been accumulating for decades. As the years have progressed these barriers have been overcome; computational capabilities have reached unprecedented heights and numerous machine learning methods and tools have been developed in the field of seismology, including the NET-VISA software, a physics-based bayesian approach, used operationally at the IDC. We will discuss further machine learning prospects for the IDC and in particular how deep learning can help the IDC enhance its capabilities regarding phase detection, identification, association as well as event location and classification.

Speaker: Mr Christos Saragiotis (CTBTO Preparatory Commission, Vienna, Austria)
• 14:31 16:16
T3.1 - Design of Sensor Systems and Advanced Sensor Technologies: Oral session Location 3 (Online)

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• 14:31
Session introduction 5m
• 14:36
Update on Xe adsorbent development at CEA/DAM 15m

In the context of the Comprehensive Nuclear Test Ban Treaty (CTBT), CEA/DAM developed about 20 years ago the SPALAX (Système de Prélèvement Automatique en Ligne avec l'Analyse du Xénon) system, which is used in the International Monitoring System to detect xenon releases following a nuclear explosion. This system is still under continuous improvement. In particular, CEA/DAM continues to work on the metal exchanged zeolites (such as [email protected]) which are very relevant with regard to the Xe uptake and purification performances. CEA/DAM developed recently a new research pilot to extend its capabilities to test such materials. This presentation aims at providing an update on CEA/DAM material developments.

Speaker: Mr Gabriel Couchaux (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France)
• 14:51
Radiation Detection for OSI – The Influence of Firmware on Detector Performance 15m

Radiation detection devices comprise a detection unit and a signal evaluation unit, each adapted for the specific application of the device. Traditionally, signals of radiation detectors were evaluated utilising analogue methods, such as the standardised NIM electronics. Developments towards compact, high-performance digital hardware resulted nowadays in the application of digital data evaluation methods, both especially useful in hand-held devices used for on-site inspections due to lower weight, lower power supply and lower costs.
The rise of digital data evaluation methods led to a variety of approaches and implementations, as no standardisation for digital data evaluation has been commonly agreed on so far. Therefore, it is essential to be aware of the influence of the implemented firmware on the detector performance.
Exemplarily, we will present our test results regarding the influence of firm- and hardware on the performance of the D3S, a wearable Radiation Isotope Identifier Device (RIID) from Kromek. The results have been gained utilising our QuTeSt (Qualification Test System for Radiation Detection Devices), a test environment to perform dynamic and static test measurements in accordance with international standards e.g. ANSI, IEC or ITRAP+10.
Powerful hand-held radiation detection devices with approved quality are of utmost importance for good OSI performance.

Speaker: Ms Monika Risse (Fraunhofer Institute for Technological Trend Analysis INT, Euskirchen, Germany)
• 15:06
Detecting underground nuclear explosion-related dynamic phenomena using time-lapse seismic surveying 15m

Underground nuclear explosions produce an immense change in pressure and temperature concentrated around the source origin. This results in the formation of characteristic static and dynamic phenomena. This study highlights the potential of using time-lapse seismic to identify ground zero by monitoring post-explosion dynamic phenomena. Time-lapse seismic is successfully employed in the oil and gas industry. It involves taking more than one 2D/3D survey at different calendar times over the same reservoir and studying the difference in seismic attributes.

Dynamic changes in rock and fluid properties due to UNE are observable for a prolonged period, even up to several decades. This is prominent near to source origin and is a result of the redistribution of residual energy, such as pressure, temperature, and saturation. Frequent seismic monitoring surveys (time-lapse seismic) would enable monitoring of changes to rock and fluid properties. The characteristics of the time-lapse seismic signature in a heterogeneous medium (or heterogeneous cavity), and the factors affecting land 4D repeatability on the 4D signature are discussed. We present a fast detection method using machine learning for the detection of explosion-related time-lapse signatures, which could be used to identify the source location or ground zero.

Speaker: Mr Shaji Mathew (Heriot-Watt University, Aberdeen, United Kingdom)
• 15:21
Distributed Optical Fiber Sensing and its Potential Application for IMS Hydroacoustic Stations 15m

Distributed optical fiber sensors (DOFSs) utilize specialized source and detection systems to convert optical fibers into linear arrays of sensors. Since early experiments in the 1980s, a range of methodologies has been developed to sense a diverse set of variables with varying sensitivities and precisions based on communication-grade as well as purpose-built optical fiber cables. Over the last decade, methods have been developed that use existing telecommunications cables to measure seismic, acoustic and temperature signals with surprising sensitivity, to sub-meter spatial resolution in some cases and with cable runs greater than 100 km in others. We review three principal techniques used to derive these measurements, together with their strengths and weaknesses, performance trade-offs, and system and environmental implementation constraints. We provide examples of existing and planned subsea implementations, and discuss the potential application of such technologies for integration into IMS hydroacoustic system sensor packages or as additional science sensors.

Speaker: Mr Geoffrey Cram (University of Washington, Seattle, WA, USA)
• 15:36
An external calibrator system for the Hyperion Sensors 15m

The NCPA has developed an external calibrator system which is nearing maturity. This calibrator is attached as a replacement sensor lid for the Hyperion sensor, and injects the signal into the back volume of the Hyperion sensor. When the external calibrator is mated to the sensor, the integrated sensor-external calibrator package behaves as a self-calibrating sensor. The external calibrator allows the Hyperion to operate nominally and without significant change in response with the external calibrator installed. The calibrator is driven by an external signal generated by the digitizer (e.g., the CAL signal on a GEOTECH). This system is capable of producing signals with amplitudes greater than 20-Pa in the operational environment between 0.01-10 Hz. We report here on the performance metrics (frequency flatness, level linearity, etc.) as well as summarize the theory of operation of the device.

Speaker: Mr Carrick Talmadge (National Center for Physical Acoustics, University of Mississippi, MS, USA)
• 15:51
Innovative on-site infrasound metrology conducted in 2019 and 2020 15m

In order to improve the confidence in the results of measurements carried out in the field, on-site metrology is a key step. With the medium-term objective of being able to deploy a portable metrology system on different infrasound stations, CEA-DAM has tested an innovative system for calibrating its infrasound sensors. The first tests were conducted in November 2019 and September 2020 as part of the installation and certification of the IMS IS25 infrasound station in Guadeloupe. A total of 20 microbarometers were qualified on site.
We present the equipments deployed, the methods used and the results of the measurements carried out. It appears that the preliminary results show a very good correspondence between the measurements performed in the field, under particular environmental conditions, and the measurements performed in the metrology laboratory. The method will be confronted to the metrology community within the framework of the European Infra-AUV project in 2022.

Speaker: Mr Paul Vincent (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France)
• 16:06
Concluding remarks 10m
• 14:45 16:15
Panel discussion on Innovation affecting CTBT – pertinent to IDC data analysis: Panel discussion Location 1 (Online)

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• 14:45
Innovation affecting CTBT: pertinent to IDC data analysis; needs, ideas and implementation pathways 1h 30m

The purpose of this panel is to generate discussion about how data and data analysis approaches can improve IDC processing, and how to go about introducing new approaches at the IDC. It will leave participants with a better understanding of where data analysis improvements are still desired by the PTS, what new tools are emerging which might be intriguing to apply to our scenarios, where new analysis approaches have made a big difference, and how things need to be tested in order to facilitate ease of acceptance at the IDC.
Themes in data analysis include moving from parameters to full waveform, using machine learning and pattern-recognizing approaches, and improving understanding of uncertainties. Discussion will include focus on these themes, and also on data-fusion applications, new pipeline paradigms, and cases where improvements in multiple areas may have non-linear improvements.

Speaker: Ms Megan Slinkard (CTBTO Preparatory Commission, Vienna, Austria)
• 14:46 16:16
T4.1 - Performance Evaluation and Modelling of the Full Verification System and its Components: Oral session Location 2 (Online)

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#### Online

• 14:46
Session introduction 4m
• 14:50
Signal injection as a means to exercise the entire CTBT monitoring regime 15m

A nuclear explosion results in a complex combination of signals including radioactivity released to the environment, seismic, infrasound, and hydroacoustic. The International Monitoring System (IMS) was established to detect these signals and analysts around the world train in the interpretation of them. However, the unique combination of signals indicative of a nuclear explosion is only fully replicated in the IMS by an actual nuclear explosion, which is a rare event. While analysts can train with synthetic data, exercising the operational IMS hardware and process was impractical until a signal injection methodology called RaFTS (Radiation Field Training Simulator) was demonstrated by Lawrence Livermore National Laboratory. Developed for radiation detectors such as those in IMS radionuclide/noble gas (RN/NG) stations, RaFTS injects pulses directly into operational detectors which are then interpreted through their electronics in the same way as real signals. Because of the universality of the RaFTS signal injection approach, it could also work with other IMS detector types, including seismic, infrasound, and hydroacoustic, thereby enabling a system-wide exercise of all IMS operating components. This presentation describes the proposed approach to enhance training and operationally exercise the entire regime. RaFTS was recently licensed for commercialization to Argon Electronics (UK) Ltd.

Speaker: Mr Steven Kreek (Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA)
• 15:05
National Data Centre Preparedness Exercise (NPE) 2019 - Scenario Design and Expert Technical Analysis 15m

NDC Preparedness Exercises (NPE) are an opportunity to practice the verification procedures for the detection of nuclear explosions in the framework of CTBT monitoring. The NPE 2019 scenario was developed in close cooperation between the Italian NDC-RN (ENEA) and the German NDC (BGR). The fictitious state RAETIA announced a reactor incident with release of unspecified radionuclides into the atmosphere. Simulated concentrations of particulate and noble gas isotopes at IMS stations were given to the participants. The task was to check the consistency with the announcement and to search for waveform events in the potential source region of the radioisotopes.
During NPE2019 an Exercise Expert Technical Analysis was requested from the IDC for the first time. A fictitious state party provided within the sceario (simulated) national measurements of radionuclides and asked for assisistance in analysing the additional samples. Especially backward ATM and the search for seismic events in the possible source region was requested. In addition the overall consistency to a scenario event, a reactor incident declared by the ficititious statr Raetia was questioned. In the third and last stage of the exercise, national regional seismic data were distributed among the particpants which contained a anomaly pointing on a explosive event.

Speaker: Mr J. Ole Ross (Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany)
• 15:20
Seismic Network Geometry Optimization Using a Fully Automated Stochastic Method 15m

One of the most important goals of any seismic network, is the ability to locate more accurately seismic events. Accordingly, accurate stations distribution, plays an important role for achieving that goal. In this study, we present a fully automated stochastic method for calculating the optimal station distribution inside a permanent/temporary seismic network. Using fuzzy self-tuned particle-swarm-optimization technique, we can do a complete search on the entire area inside the network to find the best plausible station coordinates by generating synthesized earthquakes and relocating them in a forward-inverse manner. The new stations distribution could be completely far (designing a new network) or relatively close to the current seismic network (optimizing current network). In either cases the final network pattern represents increases the accuracy of the relocated events.
We evaluated the proposed method on a data-set comprising 1562 earthquakes in Iran region (recorded by Iranian-broadband-seismic-network (BIN)) with magnitudes Mw>4.0, during 2010-2020. The maximum displacement of 25 km for each station from its initial location was considered, then the program starts to find the best coordinates. The final results showed that using the optimized seismic network, the accuracy of relocated events (based on the Hypo71 event-accuracy criteria) could be increased up to 15%.

Speaker: Dr Saeed Soltani Moghadam (International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran)
• 15:35
Bayesian localization of infrasound events with propagation metamodels 15m

Infrasound has proven to be useful for localizing events, especially in the context of the CTBT. Among the usual approaches, the Bayesian inference is often favored as it provides the posterior probability density function (PDF) for source parameters. In these methodologies, propagation models are constructed by numerically propagating signals through a set of plausible atmospheric specifications so as to obtain distributions for arrival characteristics. These approaches, however, drastically increases the number of model runs and for this reason, automatic network processing is often based either on simplified stochastic models or generative models. Such models, however, do not include the current atmospheric specifications and additional analysis is often necessary to better refine the source location estimate. In this work, we combine the Bayesian framework and recent developments in metamodeling to update the posterior PDF describing the source localization. The main difference with the standard Monte Carlo method lies in the fact that the sampling is carried out over the metamodel, which is built from an experimental design of limited size. This makes such propagation metamodels more efficient than their stochastic counterparts and better suited for real-time monitoring. The performance of the method is demonstrated through reanalyzing several recent events.

Speaker: Mr Christophe Millet (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France)
• 15:50
Metrology for low-frequency sound and vibration: A introduction to the Infra-AUV project. 15m

Infra-AUV is a new EU project that will establish primary measurements standards for low frequency phenomena across the fields of airborne and underwater acoustics and vibration (seismology). Combining expertise from the national measurement institutes and geophysical monitoring station operators, it will develop both high-precision laboratory-based methods of calibration and methods suitable for field use. Infra-AUV will also address requirements for reference sensors that link laboratory calibration capabilities to field requirements for measurement traceability.

To establish standards in the three technical areas, a variety of calibration principles will be employed, including extension of existing techniques such as reciprocity and optical interferometry, and development of new methods. There will also be an investigation of the potential for in-situ calibration methods, including use of both artificially generated and naturally occurring stimuli such as microseisms and microbaroms. The influence of calibration uncertainties on the determination of the measurands required by the monitoring networks will also be studied.

The project was strongly motivated by the CTBTO strategy to drive new metrology capability to underpin IMS data. The intention is to maintain interaction with stakeholders, not only in connection with the IMS, but with the broad range of users of low frequency acoustic and vibration data.

Speaker: Mr Thomas Bruns (Physikalisch-Technische Bundesanstalt, Berlin, Germany)
• 16:05
Concluding remarks 10m
• 16:16 16:30
Break 14m
• 16:30 17:00
Series of talks on 25 years of CTBT: Hydro-acoustic technology: Special talk Location 1 (Online)

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• 16:30
Advancements in hydroacoustic signal processing at CTBT IDC during the past two decades and plans in the future 30m

Since its establishment in 1997, the CTBT IDC has been receiving data continuously from an increasing number of hydroacoustic stations. These stations are at present composed of 11 hydrophone triplets in the ocean and 5 T-stations (seismometers) on land monitoring for nuclear explosions in the oceans. This presentation summarizes advancements in the IDC automatic processing system from the early deployment of the system receiving data from a couple of hydroacoustic stations until today’s hydroacoustic network. The advancement in IDC processing of hydrophone data has been obtained in underwater signal travel time modelling, improved rule-based signal classification, estimate of underwater signal detection and direction of arrival, introduction of early artificial intelligence for signal classification, and global network processing based on an advanced Bayesian framework (NET-VISA). These advances have improved the automatic signal classification, detection and event localization and therefore importantly reduced the amount of human interaction in the data processing. Further improvements of the processing are envisioned that includes detailed oceanographic models and databases, efficient complex signal propagation models, the Progressive Multi-Channel Correlation (PMCC) algorithm and the rapid development of machine learning algorithms. These future elements are proposed in an updated IDC automatic data processing paradigm.

Speaker: Mr Ronan Le Bras (CTBTO Preparatory Commission, Vienna, Austria)
• 16:30 18:30
T1.1 - The Atmosphere and its Dynamic: Oral session Location 2 (Online)

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#### Online

• 16:30
Session introduction 5m
• 16:35
Modeling atmospheric transport and dispersion over complex terrain 15m

The accurate simulation of atmospheric transport and dispersion requires a numerical weather prediction model that is able to resolve both mesoscale meteorology, such as a storm front or sea breeze, and microscale meteorology near the plume source, which is strongly influenced by the presence of complex terrain (i.e., mountains or dense urban development). Current generation numerical weather prediction models are excellent tools for simulating mesoscale meteorology; however, model design constraints present challenges to running at microscale resolutions over complex terrain. These challenges include, but are not limited to, overcoming model restrictions on resolved terrain slopes, parameterizing the effects of turbulent mixing, and appropriately downscaling information from the mesoscale to the microscale. A sequence of field experiments in 2019 at the Lawrence Livermore National Laboratory Site 300 included the controlled generation, observation and monitoring of plumes in a region of complex terrain. Data from these field experiments are used to evaluate model performance and inform model development that will improve the accuracy of transport and dispersion simulations over complex terrain.

Speaker: Mr David Wiersema (Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA)
• 16:50
Multi-disciplinary characterization of the June 2019 eruptions of Raikoke (Kuril Islands) and Ulawun (Papua New Guinea) volcanoes using remote technologies 15m

Retrospective eruption characterization is valuable for advancing our understanding of volcanic systems and evaluating our observational capabilities, especially with remote technologies (defined here as a space-borne system or non-local, ground-based instrumentation which include regional [15-250 km range] and remote [>250 km range] infrasound sensors). Two of the largest explosive volcanic eruptions of the past decade occurred in June 2019 at Raikoke, Kuril Islands and Ulawun, Papua New Guinea volcanoes. We integrated data from the International Monitoring System infrasound network, satellites (including Sentinel-2, TROPOMI, MODIS, Himawari-8), and globally-detected lightning (GLD360) with information from local authorities and social media to improve understanding of the eruptive behavior of these volcanoes. Remote infrasound data provide insight into changes in eruption intensity. During both eruptions, the infrasound peak frequency decreases upon transition to the Plinian phase. This may be related to changes in erupted jet and plume dynamics, such as an increase in vent diameter (observed in satellite). Our analysis illustrates the value of interdisciplinary analysis of remote data to illuminate eruptive processes.

Speaker: Ms Kathleen McKee (Carnegie Institution for Science, Washington, DC, USA)
• 17:05
Reflection on the importance of IMS-like infrasound stations in volcanologically active areas 15m

With global increases in population and air traffic, our ability to forecast when and where a hazard will occur is of prime importance. In the case of volcanic eruptions, forecasting is not limited to when and where an eruption will take place, but also when and where the impact of such an eruption will be felt. Cross-boundary volcanic ash from explosive volcanic eruptions is hazardous. The dispersal of volcanic ash could be modeled, however the level of uncertainty drastically depends on our knowledge of the eruption itself. Critical parameters are the duration of the eruption as well as the height of the associated eruptive column. With those 2 parameters you can simulate a range of plausible ash dispersal scenarios. Such parameters could be retrieved by monitoring, research sensors or an array deployed on the flank of the volcanoes. However, in a region with hundreds of active or potentially active volcanoes this is not always possible. We would like to demonstrate a few recent examples for which the IMS and IMS-like (installed in Singapore) infrasound stations were used to extract eruption source parameters.

Speaker: Prof. Benoit Taisne (Nanyang Technological University, Earth Observatory of Singapore, Singapore)
• 17:20
Global microbarom patterns: infrasound ambient noise modelling vs IMS observation database 15m

Microbarom signals are generated by wind-waves at the ocean surface and propagate all around the globe through the stratosphere and ionosphere. Microbaroms dominate the coherent infrasound ambient noise measured anywhere on Earth, with a particular peak for periods around 5 s. This ubiquitous signal can be used to monitor the medium in which it propagates, allowing to probe the properties of the middle atmosphere. Here we show the first quantitative validation of global microbarom modelling using a new source model, an ocean wave model, and atmospheric attenuation parameterization. The modelling results are compared to a reference database of microbaroms detected by the global infrasound International Monitoring System over seven years to evaluate the influence of ocean waves, source and propagation parameters. This study demonstrates that the new source model performs better than previous models, and is best when this model is combined with a wind-dependent attenuation and an ocean wave model that includes coastal reflection. Better knowledge of ambient ocean noise sources opens new perspectives to enhance the characterization of explosive atmospheric events, and provides additional integrated constraints on middle atmosphere dynamics.

Speaker: Ms Marine De Carlo (Centre National de la Recherche Scientifique (CNRS), France)
• 17:35
The Coherent Infrasound Wavefield: New IMS Broadband Bulletin Products for Atmospheric Studies and Civilian Applications 15m

Our latest comprehensive reprocessing of the IMS infrasound database covers the period from January 2003 to December 2020, representing up to 53 stations considered. The resulting catalogue of coherent signals obtained using the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration permits more accurate signal and source discrimination. Here we focus on the relation of coherent ambient infrasound to middle atmosphere dynamics and present advanced bulletin products tailored to frequency bands of specific interest by relevant user groups. These bulletin data products consist of mountain-associated wave events (0.01-0.05 Hz), a low-frequency (0.1-0.3 Hz) and a high-frequency (0.4-0.6 Hz) microbarom dataset, and observations with centre frequencies of around 1 to 2 Hz. The latter include, for instance, large fireballs and volcanic eruptions and thus provide information relevant to dedicated applications for civil security. We present selected aspects of these data products and highlight potential applications for atmospheric studies.

Speaker: Mr Patrick Hupe (Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany)
• 17:50
Obtaining the infrasound bulletin for IS08 15m

The IS08 infrasound array in Bolivia contributes to the International Monitoring System of the Comprehensive nuclear-Test-Ban Treaty Organization since 1999. Real time data, which are received at the Bolivian National Data Center (Observatorio San Calixto, OSC) through a VSAT link, are used on a daily basis for scientific and civil applications. Installed in the Central Andes, IS08 has provided valuable high quality data to the CTBTO community. In 2019, staff from the Bolivian NDC attended a basic training in Costa Rica that provided complementary knowledge in infrasound data processing. Since then, thanks to the support of the French NDC and CTBTO, the OSC staff has achieved a major step by setting up the operational chain of processing for real-time infrasound data acquisition, detection and analysis. DTK-GPMCC and DTK-DIVA are used to produce local and regional infrasound bulletins. We are now able to present our first local IS08 bulletin from 2014 to 2020, which includes a wide variety of infrasound sources observed at different seasons such as microbaroms, volcanic explosions, earthquakes (M>7) and meteors. Further improvements to our daily routine analysis to enhance our local bulletin will include the comparison with Late Event Bulletin (LEB) from CTBTO.

Speakers: Mr Gonzalo Antonio Fernandez (Observatorio San Calixto, La Paz, Bolivia) , Mr Bastien Joly (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France)
• 18:05
Low-frequency fluctuations in atmospheric pressure, temperature and wind and their relationship with global warming 15m

The work is devoted to the study of long-term data series of temperature fluctuations, wind speed and low-frequency fluctuations of atmospheric pressure, and their relationship with global climate changes. For this purpose, the data of observations of temperature, wind speed of atmospheric pressure and their fluctuations were analyzed during the time interval from January 1, 1966 to January 1, 2017. Such study was carried out for several settlements on the territory of the Russian Federation: Kaliningrad, Krasnodar, Moscow, Tiksi, Vladivostok, Yashkul. An obvious increase in air temperature over time is observed for the analyzed observation points. At the same time, a drop is observed for the wind speed in all settlements. In the Fourier spectra for data on atmospheric pressure, air temperature, wind speed, harmonics with annual, semi-annual, daily periods, as well as harmonics of daily periods - twelve hourly, eight hourly, six hourly, are distinguished. Also presented are data on changes in time of the amplitude of fluctuations of atmospheric pressure in various ranges of periods from 0.1 to 4 hours. The spectra of changes in the amplitude of these fluctuations are obtained.

Speaker: Mr Sergey Kulichkov (A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, Russian Federation)
• 18:20
Concluding remarks 10m
• 16:30 18:15
T5.2 - Experience with and Possible Additional Contributions to Issues of Global Concern such as Disaster Risk Mitigation, Climate Change Studies and Sustainable Development Goals: Oral session Location 3 (Online)

### Location 3

#### Online

• 16:30
Session introduction 5m
• 16:35
Role of CTBTO in strengthening preparedness for Disaster Risk Mitigation: A Study of Prospects and Challenges 15m

Disaster Risk Reduction is one of the most significant themes of discussion in the contemporary global debate regarding attainment of sustainable future. The CTBTO is a unique treaty which has been contributing towards Disaster Risk Mitigation with the help of its well organized verification system for years.
In 2011 when Tohoku witnessed a massive earthquake with tsunami, CTBTO monitoring stations shared critical real time information with the Japanese authority. Not only that, but after the Fukushima Daiichi nuclear disaster, the CTBTO’s radionuclide network proved enormously helpful. The verification mechanisms the CTBTO posses like International Monitoring system generate critical data which can provide timely and accurate determination of earthquakes, tsunami and volcanic eruption. To improve the efficacy of Disaster Risk Mitigation, there is a need of coherent communication and coordination amongst stakeholders, in this regards CTBTO plays a significant role.
The proposed paper will evaluate the role of CTBTO as an important stakeholder in global policy oriented debate on Disaster Risk Mitigation and assess its future prospects and challenges. It will further attempt to understand the role of CTBTO monitoring stations in different South Asian nations and its potential to emerge as an important Disaster Risk Mitigation stakeholder in the region.

Speaker: Sweta Basak (Jawaharlal Nehru University, New Dehli, India)
• 16:50
CTBTO to manage earthquake short-term risks 15m

MEMS instruments are more commonly known as inexpensive instruments to create seismic monitoring systems. As a result, independent efforts would have access to the required data stream to start analysis and applying new-generation models to continuously detecting patterns that increased creativity amid managing risks of major earthquakes. In project Earling, such data helps to distinguish high-risk seismic patterns from low risk and normal patterns. As an example, Earling issued an alert to the Icelandic Meteorological Office a few days before Iceland's largest earthquake since 2008. MEMS instruments require setup, power supply, stable connectivity, maintenance, which also are some of their constrain alongside accuracy. Utilizing accelerometers of smartphones can overcome the limitation as a mobile app would do whatever is needed to turn a smartphone into one of the nodes of a seismic network, but most of the patterns can appear in uninhabited regions with no smartphone or other instruments to record the seismic patterns. Here, the CTBTO instruments can be very useful to draw a clear viewpoint of the current risk situation in its undercover regions to detect high-risk seismic time-window when the probability of an unusual event is remarkably increased, which accurate enough especially for transferring financial risks.

Speaker: Mr Farzad Azima (Earling Ltd, London, United Kingdom)
• 17:05
Recent Seismicity of the West African Region 15m

The West African region is generally considered a stable continental area with few active tectonic features. However, several earthquakes have struck the area in historic and recent times. The region has records of damaging earthquakes dating as far back as 1615. Major events which had magnitudes between 6 and 7 occurred in 1862, 1906, 1939 and 1983. The seismicity is not well known due to the sparse seismic network coverage, incomplete and inhomogeneous earthquake catalogues and poor knowledge of the ground motion parameters. However, in recent times there have been vast improvement in the deployment of seismic equipment for monitoring earthquake activity. Seismic activities with magnitudes ranging from 1.8 to 5.3 have been observed recently in Ghana, Ivory Coast, Niger, Mali, Sierra Leone among others. These events are mostly associated with the Romanche, Chain, St. Paul transform faults and the Cameroon volcanic line. Seismic data received from the International Data Centre is utilized in compiling an earthquake catalogue for the sub region.

Speaker: Ms Paulina Ekua Amponsah (Ghana Atomic Energy Commission, Accra, Ghana)
• 17:20
The 2015 Earthquake Swarm of Fentale Volcano: Multi-hazard Threat for Ethiopia’s Access to the Coast 15m

The Fentale-Dofen magmatic segment was shown to be more active than other volcanic centers in the northern Mid Ethiopian Rift by a temporary seismic experiment, conducted between 2001 and 2003 (Keir et. al., 2006). However, the activity observed during the EAGLE experiment is not swarm like but randomly scattered in time. In this study, we characterize rarely observed seismicity in the Fentale volcano neighborhood that occurred in March and April 2015 using reasonably good quality seismic data. Over 1,350 earthquakes are located and the activity is clustered around "Tinish" Fentale, northeast of Fentale proper with a maximum magnitude of 3.5 ML. There are volcano-tectonic and long-period events, showing that the activity is induced by magmatic intrusion. This intrusion seems to commence at depth and migrate southwestward as it shallows, to the centre of the activity. This may imply that the magma feeding system of the Fentale-Volcanic Complex is either attributed to different sources or may all be influenced by the magma rich Afar Depression. This phenomenon is another geohazard threat, in addition to the lake level rise of Beseka, to Ethiopia's access to the active commercial route. This is a wakeup call to take precautionary measures to the concerned stakeholders.

Speaker: Mr Atalay Ayele (Institute of Geophysics, Space Science and Astronomy of Addis Ababa University (IGSSA), Ethiopia)
• 17:35
The sound of melting glaciers in Greenland in a changing climate 15m

The infrasound component of the IMS is not only capable of detecting nuclear-test explosions, a wide variety of natural and anthropogenic sources are continuously measured by the network.
A rich infrasonic wavefield is recorded by station I18DK, located in Northwest Greenland. I18DK is located in an unique environment far above the polar circle. Operations started in 2004, enabling long-term monitoring of its surroundings and building a statistically reliable soundscape. The infrasonic recordings reveal lots of infrasonic activity during summer, while the surroundings are infrasonically quiet in winter. The sounds are associated to glaciers around I18DK, active during the melting season. Different mechanisms like run-off and calving generate infrasound. It is found that sea and land-terminating glaciers leave a distinctly different infrasonic signature.
The simultaneous observation of sounds from different glaciers over a long time period paves the way for studying the melting behavior in the Arctic cryosphere under a changing climate. Between the years a large variability is found in infrasonic activity of the glaciers. Such activity is quantified in terms glacier dynamics by comparing it to both modeled and locally measured run-off. Sounds of the land terminating Qaanaaq glacier show an increase in activity over the years.

Speaker: Mr Läslo Evers (Royal Netherlands Meteorological Institute (KNMI), De Bilt, the Netherlands)
• 17:50
The Value of Open Data from Globally Distributed Geophysical Instrumentation Networks 15m

High-quality open data from global and regional networks such as the Global Seismographic Network and the EarthScope Transportable Array have enabled a wide range of transformative, cross-disciplinary research that has far exceeded original expectations. The networks consist of well operated and distributed stations with long-term recording histories, and were designed to facilitate studies of Earth structure and earthquake processes. However, the use of these data has been much broader, including studies of slow earthquakes, landslides, the Earth’s “hum”, glacial earthquakes, sea-state, climate change, induced seismicity, and wildfires. These broad discoveries have been enabled because datasets are completely open and unrestricted, and the data and metadata are easily discoverable and well documented.

Similarly, the International Monitoring System (IMS) has produced decades of valuable global geophysical observations in support of the CTBT explosion monitoring mission. The IMS, with its global distribution and high-quality can provide data for regions where no other data are available. Collectively, these various networks have contributed to capacity building, by providing data to scientists around the world, providing designs and standards for networks and stations worldwide, and engaging the public’s interest in science.

Speaker: Dr Robert Woodward (Incorporated Research Institutions for Seismology (IRIS), Washington, USA)
• 18:05
Concluding remarks 10m
• 17:00 18:00
Highlight talk on the Oceans and their Properties: Highlight talk Location 3 (Online)

### Location 3

#### Online

• 17:00
Improving ocean monitoring through the expansion of the global seismographic network on the seafloor 1h

There is rapidly expanding interest in the application of seismological tools for exploring the structure and dynamics of the seafloor from the inner core to the nature of the ubiquitous sediments which cover most of the seafloor. New technologies are making access to the oceans less expensive, while recently acoustic telemetry has supported the continuous transfer of data from broadband systems at the seafloor to autonomous vehicles and thence to satellites and laboratories with latencies of 2-3 minutes. The growing availability of Low Earth Orbit (LEO) communications satellites will reduce latency while increasing bandwidth.
New seafloor sensors have reduced noise levels comparable to those of the best stations on land. New batteries and compact electronics have extended seafloor lifetimes to 1-3 years. There are few barriers to growth of capabilities at rates that are comparable to consumer electronics with technological turnovers of no more than three years. Of course, this requires a continuous evolution of the seafloor technologies at a similar pace.
Novel ocean technologies have the potential of enhancing the monitoring of the ocean environment and complement the CTBTO’s hydrophone network of moored hydrophones. Surveillance systems that serve ocean data will become ubiquitous and less expensive than present systems. Overall, improved data rates and enhanced knowledge of the complex structure of the seafloor can contribute to a wide range of scientific initiatives linked to the United Nations sustainable development goals and hazard mitigation.

Speaker: Mr John Orcutt (University of California, San Diego, CA, USA)
• 18:00 19:15
CTBTO Youth Group: CTBTO Youth Group – Group of Eminent Persons Mentoring Session WebEx

#### WebEx

• 18:00
Group of Eminent Persons - CTBTO Youth Group Mentoring Session 1h

Intergenerational dialogue and mentoring are key in building the next generation of STEM and nuclear non-proliferation experts. In fields that are considered highly technical and difficult to enter, such as STEM and arms control, good mentors that provide guidance for both career and personal growth can encourage young professionals to break barriers and create lasting change. To inspire and encourage our next generation of experts to pursue their career goals, the CTBTO Youth Group (CYG) is partnering with internationally renowned leaders in STEM and disarmament from the CTBTO Group of Eminent Persons (GEM) for a virtual mentoring event.
During the session, GEM members will act as mentors and engage with students and young professionals from the CTBTO Youth Group for two rounds of short, focused conversations held under Chatham House rules. Participants will meet in Webex breakout rooms for 25 minutes on a rotating basis.
This unique opportunity will further the CYG members’ knowledge of the nuclear non-proliferation sphere, answer their most pressing professional questions and build their confidence their pursuing their interests and breaking silos in fields that require more diversity and emerging voices.

Speaker: Ms Maria Chepurina (CTBTO Preparatory Commission, Vienna, Austria)
• Thursday, 1 July
• 09:30 12:30
e-poster session - day 3: e-poster session - Theme 3 (T3.1, T3.2, T3.3, T3.5, T3.6) and T5.2 Online

#### Online

E-poster session for:
- T3.1
- T3.2
- T3.3
- T3.5
- T3.6
- T5.2

• 11:00 12:30
Panel discussion on Regional data for treaty monitoring: Panel discussion Location 1 (Online)

### Location 1

#### Online

• 11:00
Regional data for treaty monitoring 1h 30m

The International Monitoring System (IMS) was designed as a sparse global network with the purpose of detecting nuclear explosions. The sparseness of the network, the complexity of wave propagation in the Earth’s interior, the oceans and the atmosphere and the lack of accurate models that describe it limit the accuracy of the location of events detected by the IMS stations. To improve location capabilities the IMS depends on reference events, also known as ground truth events, that is, events the spatiotemporal origin of which is known with high confidence. The characterization of events as ground truth requires the use of dense national and regional networks and cooperation among National Data Centres (NDCs). Furthermore, such cooperation enhances the monitoring capabilities of the NDCs as it allows them to surpass the capabilities of the IMS. This panel will discuss the synergy between the IMS, regional experts and the NDCs and in particular the benefits Treaty monitoring has reaped from regional expert contributions, how the CTBTO contributes to regional needs and how this synergy can be facilitated and further extended in the future.

Speaker: Mr Christos Saragiotis (CTBTO Preparatory Commission, Vienna, Austria)
• 11:30 12:30
T2.3 - Seismoacoustic Sources in Theory and Practice: Oral session Location 2 (Online)

### Location 2

#### Online

• 11:30
Session introduction 5m
• 11:35
Seismoacoustic observation of surface explosions in Israel region. 15m

The International Data Center (IDC) analyze routinely seismoacoustic data for producing a list of seismoacoustic events as part of the Comprehensive Nuclear-Test Ban Treaty (CTBT) verification regime.
However, the fusion between seismic and infrasound date is not yet satisfactory.
A set of seismoacustic events with known location, origin time and if possible their energy, is necessary in order to improve our understanding,
and to calibrate our algorithms and stations.
Sayarim shooting range is located at the south of Israel, it hosted several sets of dedicated calibration explosions during summer 2009 and winter 2011.
In addition several times per year, large explosions of the order of 20-40 ton, are detonated at the range.
Some of the explosions were detected by the IMS infrasound stations.
In this work, we present the results of seismic and infrasound analysis of these explosions based on data from IMS stations and local stations.

Speaker: Mr Yochai Ben Horin (Soreq Nuclear Research Center, Yavne, Israel)
• 11:50
Seismo-acoustic data fusion: determining the best acquisition designs for multi-phenomenological monitoring campaigns 15m

For low-yield monitoring applications, the combined analysis of seismic and infrasound data could lead to significant improvements in our understanding of the processes that simultaneously generate both types of signals. Assembling datasets that contain seismic and infrasound signals generated by a single source can provide a better understanding of specific source processes. The successful combination of signals requires understanding the fidelity of infrasound measurements – especially for local, temporary instrumentation. Therefore, the first part of this presentation will focus on understanding and constructing methods by which the quality of infrasound data can be enhanced to match that of seismic data. Then, we present an in-depth analysis on the current state of seismo-acoustic data fusion and examine its use in monitoring applications. This presentation will cover a series of seismo-acoustic datasets that contain signals generated by a variety of source processes, including earthquake sequences, avalanche/landslide signals, rocket launches, and industrial explosions. We also present findings from joint analyses of these datasets to examine the unique properties of each source type. Ultimately, we determine the best acquisition designs for multi-phenomenological monitoring campaigns with a focus on seismo-acoustic data fusion.

Speaker: Ms Sarah Albert (Sandia National Laboratories (SNL), Albuquerque, NM, USA)
• 12:05
Correlating shear content in seismic source functions to scaled depth-of burial for a series of buried chemical explosions 15m

We have previously used data from the Source Physics Experiment (SPE) to relate evidence of joint slip in the near field to the yield-scaled depth-of-burial (SDOB) of buried chemical explosions in granite. A sudden surge in tangential velocity occurs in velocity records just after the passage of the peak radial shock for moderately overburied tests. This surge does not appear for nominal SDOB tests or for the “over-buried” Green’s function test. Further, we related this phenomenon to the estimated range of declared Democratic People’s Republic of Korea tests in granite and the likelihood of those tests to confuse MS:mb earthquake/explosion discrimination methods.

To render these results practical for monitoring we studied SPE seismic data to identify a SDOB effect. Through constraining the known SPE test parameters (e.g., hypocenter, velocity model) we perform a suite of source inversions with varying tensor source components. Goodness-of-fit trends between recorded seismic data and synthetic waveforms identify the source parameters, such as unexpectedly large shear contributions, that give rise to the observed tangential response in the near field. The results provide an indication that near-field joint release can contribute to the far-field waveforms as excess shear energy. LA-UR-20-29210

Speaker: Mr David Steedman (Los Alamos National Laboratory (LANL), Los Alamos, NM, USA)
• 12:20
Concluding remarks 10m
• 13:30 14:30
Highlight talk on the Atmosphere and its Dynamic: Highlight talk Location 1 (Online)

### Location 1

#### Online

• 13:30
Progress and Challenges in Atmospheric Sciences 1h

Our understanding of atmospheric processes has increased dramatically since the 19th century with important advances in observational techniques and global monitoring, numerical modeling as well as weather, climate and air quality forecasting. Efforts continue around the questions of atmospheric and climate predictability as well as the combined role of dynamical, physical and chemical processes from the lower to the upper atmosphere. The present paper will provide an historical perspective on the progress made during the last two centuries and highlight by some specific examples our ability to treat today complex questions related to the Earth system. The response of the atmospheric chemical system to the slowdown of the world economy during the COVID-19 pandemic will be presented to illustrate our current modeling and observational capability.

Speaker: Mr Guy Brasseur (Max Planck Institute for Meteorology, Hamburg, Germany)
• 13:30 15:45
T2.1 - Characterization of Treaty-Relevant Events: Oral session Location 2 (Online)

### Location 2

#### Online

• 13:30
Session introduction 5m
• 13:35
Implications of underground nuclear explosion cavity evolution for radioxenon isotopic composition 15m

Isotopic ratios of radioxenon captured in the atmosphere can be indicators of the occurrence of an underground nuclear explosion. However, atmospheric background from civilian sources of xenon isotopes can interfere with detection of nuclear testing signals according to a standard model of the evolution of radioxenon isotopic abundances in a nuclear explosion cavity. We find that this standard model is idealized by not including the effects of physical processes resulting in the partitioning of the radionuclide inventory between a gas phase and rock melt and by ignoring seepage of gases from the cavity or collapse zone. More realistic assumptions about the state of the detonation cavity produce isotopic activity ratios that differ from the civilian background more than the idealized standard model indicates, while also reducing the quantity of radioxenon available for atmospheric release and subsequent detection. Collapse of the cavity potentially has the greatest effect on partitioning of the refractory fission products that are precursors to radioxenon. The model allows for the possibility that post-detonation seismicity can be used to predict isotopic evolution.

Speaker: Mr Charles Carrigan (Lawrence Livermore National Laboratory (LLNL), Livermore, CA, USA)
• 13:50
Detecting Underground Cavities Due to UNE Using Seismic Ambient Noise 15m

Detection and location of a cavity generated by an underground nuclear explosion is an important proof in case of suspicion of violating the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The resonance seismometry is one of the CTBT’s permitted techniques during an on-site inspection (OSI).
We present a new method for detecting and locating a horizontal position of cavity which uses the Finite-interval Spectral Power (FISP) of seismic ambient noise. The method requires measurements at a set of points (possibly irregularly distributed) at the Earth’s free surface around and over a suspected cavity. Because the method gives better results for undistorted segments of noise records, we also present a method of automatic identification of such segments. We verified our method using records from a site near the Felsőpetény, Hungary, which were collected by the CTBT Organisation during a field test in the framework of developing OSI capabilities. We also show that it is possible to make the noise measurements sequentially. The minimum number of simultaneously measured locations is two. This allows to perform additional measurements, if needed, or to use a limited number of seismometers. The FISP method is ready for further tests at other sites and applications.

Speaker: Mr Jozef Kristek (Comenius University, Bratislava, Slovakia)
• 14:05
Matching Electromagnetic Measurements to Infrasound Signals 15m

Measurements of electromagnetic (EM) fields have been proposed as a means of supporting and aiding infrasound signal analysis. As opposed to nuclear explosion, other natural and man-made infrasound sources don’t produce an EM signal. Thus, if an IS signal isn’t accompanied by an EM pulse, it’s known that it’s not originated from a nuclear explosion.
Lightning discharges are the main source of EM pulses. Due to their high abundance, fortuitous coincidence of lightning with an infrasound signal are a common situation. These events may be mistakenly assumed as a nuclear explosion. To avoid this obstacle, a reliable method for lightning detection and identification is required.

EM events were detected and recognized using spectrogram. From each segmented event, both time and frequency domain features were extracted. Based on these features, and using machine learning algorithms, all the detected events could be classified as either lightning or not lightning event with high reliability. Then, the non-lightning events were matched with infrasound events. The results show that coincidences of an unrecognized EM signal with an infrasound detection are rare and thus do not impose a real limitation. We conclude that information from EM measurements may enhance and ease the analysis of infrasound signals.

Speaker: Ms Maayan Ainas Kahlon (Soreq Nuclear Research Center, Yavne, Israel)
• 14:20
Detections at IMS hydrophone stations of Primary and Tertiary phases from the sixth announced DPRK underground nuclear test 15m

Primary seismic phases, P-phases, associated with the sixth announced DPRK underground nuclear test of 3 September 2017 (DPRK6) were identified at frequencies below 4 Hz at four of the six CTBT IMS hydroacoustic hydrophone stations, namely HA01, HA03, HA08 and HA11. The signals match P-phase arrival times for these stations except for HA03, where the arrival time matches a path through the outer core. No P-phase detections were made at the two remaining stations, HA04 and HA10, likely because they fall within shadow zones of core phases. Moreover, T-phases originating from the DPRK6 event were detected at both triplets of the station nearest to the test, HA11 Wake Island, at frequencies below 10 Hz. The arrival times of these T-phases are consistent with a P-phase travelling from the source through the Earth’s crust, to an off-shore location along the Japan Trench where the bathymetry crosses the SOFAR channel and from there along water borne paths to both triplets of HA11. The back-azimuths of these T-phase arrivals point to this SOFAR crossing as the location where the P-phase coupled into the hydroacoustic paths. To the authors’ best knowledge, DPRK6 is the first nuclear test detected at IMS HA hydrophone stations.

Speaker: Mr Mario Zampolli (CTBTO Preparatory Commission, Vienna, Austria)
• 14:35
Sub-session dedicated to Beirut explosion, 04 August 2020 5m
• 14:40
Source parameters estimation of the 4th august Beirut explosion using 3D seismic modelling 15m

On 4th august 2020, A very large explosion blew up the city of Beirut, the capital of Lebanon, causing many casualties and high damage, leaving an estimated of 300000 people homeless. The explosion was caused by a large amount of ammonium nitrate stored at the port of Beirut. The CEA undertook study in order to estimate explosive source parameters – including the yield – based on the analysis of regional seismic waveforms. Data provided by the seismic stations of the International Monitoring System (IMS) have been retrieved and processed, as well as open access regional waveforms provided by IRIS and GEOFON institute. A first approach involves empirical (or semi empirical) source model, corrected of depth effect, as preconized by Ford and Walter (2014). Those preliminary results are investigated using 3D full waveform modelling, focusing on continental regional propagation through middle-east territory. 3D Green’s functions are convoluted with source term derived from seismo-acoustic coupling model. The study shows the contribution of simulation for the source analysis and parameters uncertainty mitigation.

Speaker: Mr Laurent Guillot (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France)
• 14:55
Yield Estimation of the Aug 4, 2020 Beirut Explosion Using Seismic and Shockwave Data 15m

This study uses seismic waveform and shockwave data from the Aug 4, 2020 Beirut explosion to investigate whether the yield estimated by the shockwave data can predict the spectral level observed in the seismic data. Many stations from the IRIS Data Management Center (DMC) recorded this explosion up to hundreds of kilometers with good signal-to-noise ratios (SNR). Shockwaves were recorded by personal phones and cameras, and are from social media platforms. These shockwave data were used to obtain the arrival times at various ranges. This dataset was augmented by additional data from Rigby et al. (2020). Shockwave data were modeled using published empirical and theoretical relationships, which suggested its yield to be around 1 Kt TNT. This estimate is in agreement with the value derived by Rigby et al. based on a relation they developed using the shockwave data from Kingary and Bulmash (1984). These yield estimates were used to determine the consistency with respect to the P-wave spectra, which were corrected for the propagation and attenuation effects. Accuracy of the relationships used by various investigators is also examined by validating against the shockwave data collected for other explosions with known yields.

Speaker: Mr Chandan Saikia (Air Force Technical Applications Center (AFTAC), Patrick, FL, USA)
• 15:10
Yield estimation of the 2020 Beirut explosion using open access waveform and remote sensing data 15m

We report on a multi-technique analysis using publicly available data for investigating the huge, accidental explosion that struck the city of Beirut, Lebanon, on August 4, 2020. Its devastating shock wave led to thousands of injured with more than two hundred fatalities and caused immense damage to buildings and infrastructure. Our combined analysis of seismological, hydroacoustic, infrasonic and radar remote sensing data allows us to characterize the source as well as to estimate the explosive yield. The latter ranges between 0.8 and 1.1 kt TNT (kilotons of trinitrotoluene) equivalent and is plausible given the reported 2.75 kt of ammonium nitrate as explosive source. Data from the International Monitoring System of the CTBTO are used for infrasound array detections. Seismometer data from GEOFON and IRIS complement the source characterization based on seismic and acoustic signal recordings, which propagated in solid earth, water and air. Copernicus Sentinel data serve for radar remote sensing and damage estimation. As there are strict limitations for an on-site analysis of this catastrophic explosion, our presented approach based on openly accessible data from global station networks and satellite missions is of high scientific and social relevance that furthermore is transferable to other explosions.

Speaker: Mr Christoph Pilger (Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany)
• 15:25
Seismo-Acoustic signature of Beirut Port Explosion 15m

A large amount of ammonium nitrate has exploded in Beirut port on 4 August 2020 leaving behind large destruction. The explosion has triggered seismic, acoustic, infrasound, and hydroacoustic signals that propagated through the lithosphere, atmosphere and hydrosphere. The signal was widely recorded in the neighboring countries and even in the case of infrasound, it has been reported regionally. In this work we document the seismo-acoustic signature of the event and try to investigate the size of the source and the deformation associated with it, using different techniques. DInSAR analysis verified maximum damage area, extending 2 km around the blast site with two cm vertical displacement. Several local and regional seismological stations recorded three different phases from this event with velocities 7.92 km/s, 1.34 km/s, and 0.35 km/s respectively. These phases represent P waves, hydroacoustic signals, and shockwave signals, respectively. The propagation modeling of the infrasound waves reflects a westward propagation towards I48TN, I26DE, and I17CI infrasound stations of the International Monitoring Stations (IMS) of the Comprehensive Test Ban Organization (CTBTO). The location of the explosion is estimated accurately from the waveform data of the recording stations using the technique of the Progressive multi-channel cross-correlation

Speaker: Mr Mohamed Nabil Mohamed ElGabry (National Research Institute of Astronomy and Geophysics (NRIAG), Helwan, Egypt)
• 15:40
Concluding remarks 5m
• 13:30 14:30
T4.3 - IT, Power Systems and other Enabling Technologies: Oral session Location 3 (Online)

### Location 3

#### Online

• 13:30
Session introduction 5m
• 13:35
Seismic-Hydroacoustic-Infrasound (SHI) in the Sky: benefits and pitfalls of NDC-in-a-box in the Cloud 15m

Capacity building efforts for National Data Centers (NDCs) commonly involve the provisioning and shipment of physical hardware systems and the training, installation, maintenance and distribution of the “National Data Centre (NDC)-in-a-Box” (NIAB) software suite. These fundamental functions (access to hardware and software) are the foundations of cloud computing. We investigate whether utilizing cloud infrastructure is feasible and beneficial to users of the IMS data and IDC software. We test using basic cloud computing and storage technologies to increase access and capacity for NDCs/users, to decrease cost and logistical burden, increase processing capabilities, and improve overall infrastructure reliability without losing the current level of local flexibility. We investigate the use of VirtualBox virtual machines (VMs), Docker containers, and Amazon Machine Images (AMIs) on elastic compute cloud (EC2) virtual hardware in the Amazon Web Services commercial cloud. Thus far we have found that AMIs offer the best balance of high configurability and low resource usage. Internal and external evaluations of AMIs containing NIAB Seismic, Hydroacoustic, and Infrasound (SHI) software and virtualized desktop environments on EC2 instances note good desktop responsiveness and adequate computing and storage capacity.

Speaker: Gordon MacLeod (Los Alamos National Laboratory (LANL), Los Alamos, NM, USA)
• 13:50
Next-generation IMS Power Systems: Current status and the way forward 15m

With a strong mandate to sustain high annual data availability throughout the IMS network, IMS/ED launched the initiative to design the next-generation IMS power systems to strengthen IMS stations’ resiliency to catastrophic failures, often arising from power-related issues. Five standardized IMS power system prototypes were developed, certified, and subjected to throughout factory-acceptance testing. The developed next-generation IMS power systems are based on the open system architecture concept, utilizing ad-hoc selection and substitution of various power sources and power system components derived from the environmental demands and logistical restrictions present at the station location. These purpose-built, yet standardized power systems thus adapt to the site-specific input and output requirements, without requiring extensive redesign and cost when deployed at other stations throughout the IMS network. The high degree of standardization simplifies installation, maintenance and future upgrades as components can be freely interchanged throughout their life cycle without impacting the overall system.
The new IMS power systems are currently undergoing long-period testing in field conditions at the FACT facility at Sandia National Laboratories, with further tests scheduled at a test site in Alaska in 2021. The drafting and release of the IMS Power System Guidelines documentation is underway.

Speaker: Mr Marian Jusko (CTBTO Preparatory Commission, Vienna, Austria)
• 14:05
Presentation of containerized solution and optimized power supply system 15m

The aim of this presentation is to introduce a range of new engineering systems recently developed and installed by Enviroearth and adapted to the whole IMS network. We will present a modular power supply system which allows flexibility to answer to any power supply need and configuration over the global network. These power systems are all equipped with their own state of health IT system allowing a continuous monitoring of information on the system operation via an accessible and user friendly dashboard. We will also present a series of plug and play equipment vaults and containerized system technologies that have been optimized to fit with all the topologies and technologies of the station within the IMS network. Over the past few years, we have worked on the improvement and the standardization of these systems to target more robustness and sustainability leading to better station data availability. We would like to present this knowledge and expertise on these products and introduce state-of-the-art systems adapted to the needs of the CTBTO with a focus on the verification options and assets that they are all offering.

Speaker: Clement Bednarowicz (Enviroearth, Saint-Cannat, France)
• 14:20
Concluding remarks 10m
• 14:30 15:00
Series of talks on 25 years of CTBT: On-Site Inspections: Special talk Location 1 (Online)

### Location 1

#### Online

• 14:30
Development of the first comprehensive draft list of equipment for use during OSIs 30m

The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (Commission) is required to develop and prepare a list of equipment for use during on-site inspections (OSIs). The Commission started work on this verification task as early as during the first OSI workshop in 1997 and has since considered both the structure of the list and the specifications of the equipment to be listed.
A proposal for the first comprehensive draft list of equipment for use during OSIs has been presented by the Provisional Technical Secretariat of the Commission as a result of the implementation of OSI Action Plan 2016-2019. Taking into account relevant Treaty provisions and guidance from the Commission’s policy making organs, it covers all permitted inspection activities and techniques with the exception of drilling and is currently undergoing review by States Signatories.
This presentation provides a summary of the development of the first comprehensive draft list of equipment for use during OSIs from the outset. It highlights how advances of science and technology have influenced proposed specifications of OSI equipment since the CTBT opened for signature and outlines why the draft list will mark an important milestone in the development of OSI capabilities.

Speaker: Mr Gregor Malich (CTBTO Preparatory Commission, Vienna, Austria)
• 14:30 15:45
T4.4 - Network Sustainability and systems engineering for CTBT Verification: Oral session Location 3 (Online)

### Location 3

#### Online

• 14:30
Session introduction 5m
• 14:35
Activities to improve Data Availability by the IMS Maintenance Unit 15m

Maintaining and improving data availability (DA) of certified IMS stations require the joint efforts of the states hosting International Monitoring System (IMS) stations, local operators and the PTS. Activities that are being undertaken in areas of maintenance, operations, engineering, development, logistics, recapitalization and training across the PTS directly impact the DA and sustainability of the IMS. This paper provides a summary of some key activities undertaken by the IMS Maintenance Unit to improve data availability. These include; equipment standardization, improved hands on technical training, HPGe detector vacuum restoration, improved sparing, improvements to power systems, grounding and lightning protection, infrastructure improvements and equipment upgrades, monitoring HPGe detector SoH and spectral data quality to perform predictive maintenance and improvements to the station environment.

Speaker: Mr Nicholas Mascarenhas (CTBTO Preparatory Commission, Vienna, Austria)
• 14:50
Advanced algorithms and prognostics for monitoring the Radionuclide Aerosol Sampler/Analyzer (RASA) 15m

State of health (SOH) data from radionuclide sensors in the International Monitoring System (IMS) provides critical information about the operating status of stations. Radionuclide systems typically have many sensors that are important indicators of normal operation or system problems. Since there are many IMS stations with radionuclide systems, monitoring them all simultaneously by a single analyst is a challenge. Over the past several years Pacific Northwest National Laboratory (PNNL), in collaboration with General Dynamics, has been developing a status of health monitoring architecture for analyzing SOH data from radionuclide systems of the IMS. The architecture was originally developed to support the Swedish Automatic Unit for Noble gas Acquisition (SAUNA). Recently, the Radionuclide Aerosol Sampler/Analyzer (RASA) was added to the SOH monitoring tool. The tool uses statistical methods such as Exponential Weighted Moving Average (EWMA) and standard deviation techniques to monitor the systems. PNNL is now investigating methods to improve RASA SOH monitoring capability by using advanced algorithms capable of identifying actual failures based on sensor signatures. This research is also seeking to detect and identify the failures as early as possible using advanced prognostic approaches. The results from failure identification techniques and prognostic algorithms will be outlined and presented.

Speaker: Mr Reynold Suarez (Pacific Northwest National Laboratory (PNNL), Richland, WA, USA)
• 15:05
AFTAC’s Approach to Evaluating Sustainment Variance Impacting Mission Performance 15m

AFTAC’s Center of Engineering Excellence (CoEE) understands that system variance imposes risks to both network performance and budget parameters. Left unchecked, these risks create severe consequences to AFTACs global sensor network. As a result, the CoEE has built upon previous evaluation of maintenance support strategies (O&M 2020) to identify and eliminate the largest sources of maintenance variance. The CoEE has analyzed nearly ten years of historical performance field data, process instructions, training procedures, personnel requirements, and other documentation to assess maintenance activity impacting the USAEDS Network performance and requiring additional unwarranted costs. The CoEE has made significant progress eliminating those sources of variance, improving control of network performance, and eliminating unnecessary costs. The findings resulting from this study are the cornerstone that will allow AFTAC to strategically reshape geophysical operations towards a future emphasizing agility, performance, and cost sensitivity.

Speakers: Mr Stephen Poindexter (Air Force Technical Applications Center (AFTAC), FL, USA) , Mr Robert Martin
• 15:20
Operating temporary seismic array during modernization of IMS station 15m

The PS19 seismic station (GERES) is part of the IMS primary seismic network for verification of the CTBT. The station consists of 25 array elements with an aperture of about 4 km. The modernization of GERES in 2017/2018 implicated a general shutdown of the operation for 18 months, since the intra-array cabling was replaced and new equipment for power supply and data acquisition was installed. However, the absence of this station would have unacceptably decreased the network performance in Europe. Therefore, the operation of a temporary 10-element seismic array guaranteed a continuous data recording with sufficient detectability of seismic signals at this IMS location. The selected configuration has proved successful, that the high performance as is known at GERES could be sustained during the period of construction works. A crucial prerequisite was the high data availability, which was achieved due to reliable set-up of the station equipment. Robust mobile containers housing equipment for power supply, data acquisition and transmission were installed at the individual array elements nearby the vaults, where the seismometers remained at the original position. Especially, the operation of direct methanol fuel cell systems with remote monitoring has proved as technology with high operational reliability.

Speaker: Mr Lukas Menke (Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany)
• 15:35
Concluding remarks 10m
• 15:00 16:00
The 25th anniversary for opening the CTBT for signature: invited talk on Challenges of On-Site Inspections: Invited 25th anniversary talk Location 1 (Online)

### Location 1

#### Online

• 15:00
Status of Preparations for the Support of On-site Inspections 1h

Twenty-five years ago, in 1996, the opening of the CTBT for signatures was followed by the Resolution of the General Assembly on establishing the Preparatory Commission (PrepCom) for the CTBTO (Resolution). According to this Resolution the PrepCom is required to make all necessary preparations for the support of on-site inspections (OSI) from the entry into force of the Treaty.
This contribution will provide an overview of the remarkable development and interrelationship of OSI capabilities particularly regarding the methodology for the planning and conduct of an inspection, the application of the permitted inspection techniques and the training of (surrogate) inspectors. It will also assess the status of preparations as specified in paragraph 15 of the Annex to the Resolution. Examples of co-operation between the States Signatories and the Provisional Technical Secretariat will illustrate some of the achievements.
Ongoing technical developments and innovations will be discussed with a view to identifying opportunities for further improvement of OSI capabilities within the framework of the Treaty and its Protocol in order to make inspections more efficient and effective. Finally, thanks to the current status of the OSI capabilities, the potential for and ideas on using these capabilities for civil applications will be presented as well.

Speaker: Mr Peter Labak (Earth Science Institute, Slovak Academy of Sciences, Bratislava, Slovakia)
• 16:15 16:45
Series of talks on 25 years of CTBT: Infrasound technology: Special talk Location 1 (Online)

### Location 1

#### Online

• 16:15
Infrasound processing system at the IDC, from rudimentary to maturity 30m

In 2001, when the first data from an IMS infrasound station started to arrive in near real-time at the IDC, its infrasound processing system was in a premature state. The IDC then embarked for a multi-year design and development of its dedicated processing system, which led to operational IDC automatic processing and interactive analysis systems in 2010. The IDC went on in the next ten years to produce over 40,000 infrasound events reviewed by expert analysts.
In an effort to continue advancing its methods, improving its automatic system and providing software packages to CTBTO users, the IDC focused on several projects. First, the automatic system for the identification of valid signals was redesigned with the development of DTK- PMCC (Progressive Multi-Channel Correlation), which is made available to CTBTO users within NDC-in-a-Box. And second, an infrasound model was developed for automatic waveform network processing software NET-VISA with an emphasis on the optimization of the network detection threshold by identifying ways to refine signal characterization methodology and association criteria.
Future improvements of the IDC processing system are planned to further reduce analyst workload that includes atmospheric propagation modeling and enhancements of the automatic pipeline components.

Speaker: Mr Pierrick Mialle (CTBTO Preparatory Commission, Vienna, Austria)
• 16:15 17:15
T3.2 - Laboratories Including Transportable and Field Based Facilities: Oral session Location 2 (Online)

### Location 2

#### Online

• 16:15
Session introduction 5m
• 16:20
Long-term verification of radionuclide laboratory gain and efficiency stability 15m

As radioxenon samples are collected around the world at the CTBTO IMS stations, a subset of those are sent to radionuclide laboratories around the world for re-analysis. PNNL operates the U.S. Noble Gas Laboratory (US-NGL), which was certified in December of 2016. There is also an opportunity to utilize the radioxenon laboratories in a field system comparison experiment. In this presentation, we detail current and potential future methods of utilizing the radioxenon laboratories. For a laboratory system to be used for verification of continuously operating systems, it is important to routinely validate the energy and efficiency calibration of the laboratory system. We discuss long-term verification measurements made for USL16-NGL and the methods utilized to ensure stable operation. Additionally, we present the impact of the enhanced throughput on such scenarios and how to ensure that the operational role is maintained during experiments.

Speaker: Mr Michael Foxe (Pacific Northwest National Laboratory (PNNL), Richland, WA, USA)
• 16:35
A high-resolution laboratory-based beta-gamma coincidence spectrometry system for radioxenon measurement 15m

GBL15, the UK’s noble gas certified Comprehensive Nuclear-Test-Ban Treaty (CTBT) radionuclide laboratory supports the International Monitoring System (IMS) through measurement of environmental radioxenon samples using beta-gamma coincidence spectrometry. GBL15 currently utilises a system comprised of NaI(Tl) photon detectors and plastic scintillator electron-detectors to measure coincident emissions from the four radioxenon isotopes of interest: Xe-133, Xe-135, Xe-131m and Xe-133m. A high-resolution electron-photon coincidence detector system comprising of high-purity germanium (HPGe) detectors and a PIPSBox detector demonstrates improved discrimination between signals and less interference compared to the current system. The minimum detectable activities (MDA) and coincidence detection efficiencies for the radioxenon isotopes of interest have been quantified.

Speaker: Mr Matthew Goodwin (AWE Aldermaston, Reading, United Kingdom)
• 16:50
Installation for the measurement of low activities of 37Ar based on the detection of liquid argon scintillation 15m

One of the most conclusive evidences of a violation of CTBT is the presence in the subsoil air of elevated concentrations of 37Ar radionuclide, which is formed in large quantities in the interaction of neutrons with calcium in rocks.
Traditionally, to measure the activity of 37Ar, proportional gas counters are used, which are filled with a counting gas prepared from samples of argon with the addition of methane. Further reduction of the detection limit of 37Ar is limited by the difficulty of a significant increase of argon sample volume placed in a proportional counter.
Installation for the detection of argon-37 low activities based on the liquid scintillation principle was developed at the Khlopin Radium Institute under contract with the CTBTO. The role of the scintillator in this installation is performed by the liquefied preparation of extracted from soil air argon itself. The use of liquefied argon samples allows one to multiply the volume of the measured samples without increasing the size of the measuring cell and shield elements, and allows significant reduction of detection limits of 37Ar.
The presentation contains a description of the installation and the results obtained after its testing.

Speaker: Mr Sergei Pakhomov (Khlopin Radium Institute, St. Petersburg, Russian Federation)
• 17:05
Concluding remarks 10m
• 16:16 17:46
T1.3 - The Oceans and their Properties: Oral session Location 3 (Online)

### Location 3

#### Online

• 16:16
Session introduction 4m
• 16:20
Seismic ocean thermometry using CTBTO hydrophone data 15m

As the major buffer of Earth’s energy imbalance, the ocean plays a key role in regulating global climate and temperature changes. However, accurate estimation of global ocean temperature change remains a challenging sampling problem. To complement existing point measurements, we have developed a novel and low-cost method of using travel time changes of acoustic waves from repeating natural earthquakes to infer basin-scale average ocean temperature changes. In this study, we implement this method using the CTBTO hydrophones H08 near Diego Garcia in the central Indian ocean and H01 near Cape Leeuwin off the southwest coast of Australia. We use the ISC cataloged earthquakes as templates to conduct template matching and obtain a more complete set of repeating earthquakes in 2005–2016 around the Nias Island off Sumatra. Adding these new detected earthquakes and using high-quality hydrophone data enable us to infer the large-scale ocean temperature changes with a high temporal resolution. For both H08 and H01, we detect not only seasonal signals generally consistent with that in previous oceanographic datasets of ECCO and Argo, but also more interesting features missing in ECCO and Argo. These results suggest that the global hydrophone network offers new opportunities for monitoring ocean warming.

Speaker: Mr Wenbo Wu (California Institute of Technology, CA, USA)
• 16:35
Using ambient noise at hydroacoustic stations for passive ocean sensing 15m

Conventional acoustic remote sensing techniques typically rely on controlled active sources which can be problematic to deploy and operate over the long term - especially if multiple sources are required to fully illuminate the ocean region of interest - or may not even be available at very low frequencies (∼10 Hz). Conversely, receiver arrays are becoming increasingly autonomous, and capable of long term deployment thus enabling passive acoustics for ocean remote sensing applications by taking advantage of the ubiquitous ocean ambient noise. The archived ambient noise recordings made at the hydroacoustic stations of the Comprehensive Nuclear-Test-Ban Treaty (CTBTO) International Monitoring System (IMS), over decades at some locations, provide a unique platform for the scientific community to test this fully passive acoustic approach for ocean remote sensing. This presentation will present proof of concept of passive ocean remote methods using these hydroacoustic data such as passive acoustic thermometry to estimate deep ocean temperature variations and internal tides using coherent processing of low-frequency ambient noise. Challenges and opportunities for Ocean basin and global-scale passive ocean sensing will be discussed.

Speaker: Mr Karim Sabra (Georgia Institute of Technology, GA, USA)
• 17:05
Long-term observations of a potential great whale call from the central Indian Ocean during 2002-2019 15m

This work presents observations of a potential great whale call at Diego Garcia (HA08N and HA08S). The whale calls which remain unidentified have only been referred to as the Diego Garcia Downsweep (DGD). The calls occur between 20-45 Hz, and constitute a set of tones similar to a comb, followed by a downsweep. The calls between 2002-2019 are used to present two analyses. The first shows that the DGD call-frequencies change across the years. The comb frequencies steadily increase, while that of the downsweep decrease but also branch into higher frequencies. The second set of results present angle and range estimates of the whale. For angle estimates this work uses a broadband beamformer which incoherently combines narrowband beamformer outputs across the multiple frequencies of the calls. For range, the work builds an Nx2-dimensional Parabolic Equation (PE) model to predict the received intensities across range. The model incorporates the local sound speed profiles, and the complicated bathymetry across a 1500 km area around HA08. The intensity predictions are compared against the received call levels to estimate ranges of the calling whales. Preliminary results show that the estimates pick out tracks of nearby whales, and some potentially distant calls.

Speaker: Ms Nikita R. Pinto (Indian Institute of Technology Madras, Chennai, India)
• 17:20
SMART Subsea Cables for Observing the Ocean and Earth: An Update 15m

JTF SMART Subsea Cables (Joint Task Force, Science Monitoring And Reliable Telecommunications) is working to integrate environmental sensors (temperature, pressure, seismic acceleration) into submarine telecommunications cables. This will support climate and ocean observation, sea level monitoring, observations of Earth structure, tsunami and earthquake early warning and disaster risk reduction, with relevance to the CTBTO monitoring mission. Recent advances include regional SMART pilot systems that are initial steps to trans-ocean and global implementation. Building on the OceanObs’19 conference and community white paper (DOI 10.3389/fmars.2019.00424), this overview and description of the status of ongoing projects will include: The InSea wet demonstration project off Sicily at the EMSO Western Ionian Facility; Vanuatu and New Caledonia; Indonesia’s Makassar Strait systems working toward systems for the Sumatra-Java megathrust zone and in the inner waters; and the CAM-2 triangle system connecting Lisbon, Azores and Madeira. Observing system design studies are reviewed. Funding reflects a blend of government, development bank, and commercial contributions. In addition to these notable scientific and societal benefits, the Telecom mission of societal connectivity will benefit as well, as environmental awareness improves both individual cable system integrity as well as that of the overall global communications network.

Speaker: Mr Bruce Howe (University of Hawaiʻi at Mānoa, HI, USA)
• 17:35
Concluding remarks 11m
• 16:45 17:45
The 25th anniversary for opening the CTBT for signature: invited talk on Infrasound technology: Invited 25th anniversary talk Location 1 (Online)

### Location 1

#### Online

• 16:45
25 years of infrasound monitoring: achievements and new challenges 1h

The infrasound International Monitoring System (IMS) is a unique tool for atmospheric observations due to its high capacity for long-range detection and localisation. Its development motivated technological innovation in sensors, array stations and automatic detection algorithms. The rapidly increasing number of certified stations provided a large diversity of man-made and natural events, well identified thanks to their precise description. Numerical simulations, based on revisited propagation laws, quantified its high performances and variability. Data analyses then clearly demonstrated that the simulation uncertainties originate from the middle atmosphere variability, which controls the infrasound waveguides and is under-represented in models. Unexpectedly, relevant atmospheric parameters were identified in signals from well-known sources such as volcanoes, opening new remote sensing possibilities. The IMS is associated to complementary networks in the Atmospheric dynamics Research InfraStructure in Europe (ARISE) framework, providing an improved description of the middle atmosphere disturbances relevant both for infrasound monitoring and applications such as medium-range weather predictions. Today, archived data reveals climate change effects on specific events such as icebreaking or lightning activity and a remote volcano monitoring system is developed to provide alert to civil aviation, showing the high IMS potential for weather, climate and civil security applications.

Speaker: Ms Elisabeth Blanc (Commissariat à l’énergie atomique et aux énergies alternatives (CEA), France)
• 17:15 17:35
Preceding talk on Human versus Machine
• 17:15
Knowledge vs Data 20m

For most of its history, AI focused on knowledge-based systems -- that is, systems that know things and can reason with that knowledge. In the preceding decade, knowledge was replaced by data and reasoning disappeared. Unfortunately, the absence of knowledge means that modern AI systems based on deep learning require vast amounts of training data and generalize very poorly. In contrast, humans know a lot and learn effectively from very few examples. This is not a
coincidence. It is entirely possible to combine knowledge and data, reasoning and learning. One technology that does this is
probabilistic programming, which combines several important ideas from mathematics including logic, probability, and universal machines. I will illustrate these ideas in the context of CTBT monitoring.

Speaker: Mr Stuart Russell (University of California, Berkeley, CA, USA)
• 17:35 19:05
Panel discussion on Human versus Machine: Panel discussion Location 2 (Online )

### Location 2

#### Online

• 17:55
Human versus Machine 1h 10m

Big Data, Machine Learning (ML), and Artificial Intelligence are more and more parts of our daily lives with applications such as self-driving cars, multimedia streaming and shopping suggestions, identification of financial crimes, and medical diagnosis.
For CTBT, early adoption of ML methods took place in the 1990s with applications ranging from the monitoring of the network, to data processing and analysis, to the way OSI inspections can be conducted. The methods currently in place could probably be boosted by incorporating improved algorithms, for instance with the use of full waveform-based approaches, and by making full use of the twenty years of accumulated data. Progress has been made recently with a Bayesian approach for network processing.
Even though overall results of applying ML methods are often impressive, domain experts may formulate objections to their use. Reasons may be:
• Skepticism that an ML algorithm would find a solution if the learning data set does not contain an exact example of the result. Are Bayesian methods a way to dispel these criticisms?
• Interpretation of the results. How can a particular result be explained to an expert or a client when many ML methods have imbedded decision-making processes which remain opaque to the user?

Speaker: Ms Heidi Kuzma (LRH Energy Capital LLC, CA, USA)
• 17:46 19:01
T3.3 - Remote Sensing, Imagery and Data Acquisition Platforms: Oral session Location 3 (Online)

### Location 3

#### Online

• 17:46
Session introduction 5m
• 17:51
Performance Evaluation of the Pixel-Object Fusion Algorithm for Change Detection in Use of Countering Nuclear Proliferation 15m

For countering nuclear proliferation, the structural changes within the suspicious area have to be carefully monitored. Due to the restriction of access to rogue states, the level of change is highly dependent on the spatial resolution of satellite imagery. As increasing the quality and quantity of the imagery, the semi-automated change detection process has been studied in support of the interpretation. Nonetheless, the availability of various methods rather focused on case studies, and the results are qualitatively discussed in general. In a practical perspective, ultimately the performance has to be reviewed quantitatively so that field users can understand usability and unusability of the semi-automated system. Further, it leads to how to supplement the state-of-art technologies for field use. With this background, this paper presents the change detection algorithm developed by Korea Institue of Nuclear Nonproliferation and Control (KINAC), which integrates pixel and object advantages in computer vision, and quantitatively evaluates the performance with accuracy indices. For the semi-automated change detection, incompatibility between the recall and false discovery rate is discussed numerically. It is concluded that effective threshold values for the semi-automated change detection can be derived from the optimisation perspective, although it must vary depending on the purpose of use.

Speaker: Mr Jae-Jun Han (Korea Institute of Nuclear Nonproliferation and Control (KINAC), Daejeon, Republic of Korea)
• 18:06
Geospatial Automated Imagery Analysis tool (GAIA): incorporating time-series satellite data to detect changing site conditions 15m

In order to reduce uncertainties and improve confidence in analyses of potentially anomalous events, accurate event locations are required. However, event location/relocation and replicability can be difficult due to a number of factors, e.g., variability in seismic data processing and spatially sparse network coverage. By leveraging commercially available, high-fidelity satellite data as a supporting data stream, time-separated images could (1) build confidence in seismic data analyses and (2) identify specific areas where change has occurred, such as building construction/demolition or road/facilities improvements. We summarize a novel geospatial processing tool – GAIA: Geospatial Automated Imagery Analysis – that automates image orthorectification and change detection of time-separated images. GAIA is an easy-to-use, ArcGIS-based toolbox with a standardized workflow for image analyses and change detection that significantly reduces geospatial processing time (from hours to <5 minutes). We present the GAIA functionality through relevant exemplar cases with a focus on underground explosions at the Nevada National Security Site (U.S.A.). The use of GAIA in monitoring and verification applications could support event analyses through effective and consistent use of commercially-available satellite imagery. GAIA shows promise for identifying locations of anomalous change and reducing uncertainty in event locations.

Speaker: Ms Elizabeth Miller (Los Alamos National Laboratory (LANL), Los Alamos, NM, USA)
• 18:21
Unattended Ground Sensing and In-situ Processing of Geophysical Data 15m

Seismic monitoring systems are typically emplaced along with a complementary infrastructure for power and data exfiltration. In some instances, it may be desirable to deploy a system in a location where it is not feasible or reasonable to provide such infrastructure. In this case there are numerous commercial options that can provide continuous recording and indefinite operation using solar power. However, these locations must still be visited on occasion to retrieve data. We have developed a system that allows for both continuous monitoring and deployment of semi-complex algorithms. Satellite and cellular communications provide a both the ability to retrieve data and command/control of the sensor platform. This platform provides for the ability to deploy complex detection and/or classification algorithms to reduce the need to send back continuous data. A system has been deployed at the Redmond Salt Mine in southwestern Utah, USA since October of 2018. A 1-D convolutional neural network (CNN) inference model has been implemented on the unit as an exemplar to demonstrate the ability to classify seismic signals from explosive blasting at the salt mine. The CNN was trained on a dataset labeled by mine level and achieved a F1 Score of 0.802 with the testing set.

Speaker: Mr William O'Rourke (Sandia National Laboratories (SNL), Albuquerque, NM, USA)
• 18:36
Commercial UAV Based Magnetic Field Mapping Solution to OSI 15m

Based on the lessons learned during the past training and exercise experiences, especially IFE08 and IFE14, inspection efficiency and health & safety concerns are very important factors for conducting ground or airborne magnetic field mapping. This work would propose an UAV based magnetic mapping system, which is also the active result of joint efforts made by experts of OSI and commercial magnetic mapping application. The system is composed mainly of UAV, magnetic mapping sensor arrays as payload, ground based station subsystems. UAV platform is specially designed to minimize its own magnetic field to reduce the interference to the magnetic detection to the minimum. Quantum magnetic detector has been utilized to achieve the sensitive detection of magnetic field over 100 times more accurate than ordinary magnetic detector. Ground based station would achieve UAV flight-control and real-time magnetic mapping data visualization and analysis. The whole UAV based magnetic field mapping system would achieve mapping of 20000 m2 inspection area per hour with the flight speed of 4 m/s and detection width of 2 meter. Detection of metal anomalies with sensitivity ranging from 0.5 nT to 10 nT could be conducted with the detection depth from 3 meter to 60 meter.

Speaker: Mr Peng Li (Hope investment Development Corp. Ltd., Beijing, China)
• 18:51
Concluding remarks 10m
• Friday, 2 July
• 09:30 12:30
e-poster session - day 4: e-poster session - Theme 4 (T4.1, T4.3, T4.4, T4.5) and T5.1 Online

#### Online

E-poster session for:
- T4.1
- T4.3
- T4.4
- T4.5
- T5.1

• 10:30 11:00
Invited talk on Risk Mitigation: Invited talk on risk mitigation Location 1 (Onnline)

### Location 1

#### Onnline

• 10:30
Use of infrasound data for early notification of Volcanic Ash Advisory Centres 30m

Continuous progress has been made in the potential use of infrasound data in support of the International Civil Aviation Organization (ICAO) International Airways Volcano Watch. This work was initiated by a collaboration between CTBTO and the Toulouse Volcanic Ash Advisory Centre (VAAC), resulting in the development of the Volcanic Information System (VIS), under the ARISE (Atmospheric dynamics Research Infra-Structure in Europe) project. VIS provides notifications of possible volcanic activity based on infrasound observations by stations in the IMS (International Monitoring System) and other national or research installations. After successful tests using recent eruption data, an alerting bulletin prototype based on VIS has been designed for Toulouse VAAC. Two types of notifications are worthwhile: one in the far field (for early detection of eruptive activity and possible ash emission from poorly instrumented explosive volcanoes); and one in the close field (to enrich the description of the kinetic energy of the eruption and of the volcanic ash release). ICAO and World Meteorological Organization (WMO) encourage the effort to continue with the extension of the proposed approach to other VAACs. This essential step will help in designing new automated products that could contribute to reducing the impact of ash clouds on aviation.

Speaker: Mr Philippe Hereil (Meteo France, VAAC Toulouse, France)
• 11:00 11:20
Preceding talk on Synergy among monitoring systems to address hazard mitigation and global challenges
• 11:00
Welcome to risk: As we know it or, do we? 20m

Risk is systemic, interconnected and cascading. The COVID-19 pandemic has just sent a stark reminder to the world that the days of one hazard, one impact are over. A NATECH event like a tsunami leading to a nuclear disaster is just another manifestation of the cascading nature of risk. Climate change is further driving risk across borders, with impacts on all sectors and with long-lasting, debilitating socio-economic and environmental consequences. The people hit hardest are those who have done the least to cause these significant changes.
It is this complex nature of risk that underpins the Sendai Framework for Disaster Rick Reduction 2015-2030 that marks a paradigmatic shift towards a prevention lens for disaster risk management. UNDRR supports UN Member States in strengthening their risk knowledge, monitoring and capacity-development to accelerate risk-informed development pathways and humanitarian action.
As Member States move forward with the 2030 Agenda, they need to identify and analyse the broad range of risks they face and put in place appropriate measures to address the systemic nature of risk. ‘Business as usual’ approach will keep us off-track the development trajectory and we need a transformative change to enhance the resilience of the planet and its people.

Speaker: Ms Loretta Hieber-Girardet (United Nations Office for Disaster Risk Mitigation, Geneva, Switzerland)
• 11:20 12:30
Panel discussion on Synergy among monitoring systems to address hazard mitigation and global challenges: Panel discussion Location 1 (Online)

### Location 1

#### Online

• 11:20
Synergy among monitoring systems to address hazard mitigation and global challenges 1h 10m

This panel will discuss existing or potential synergies between the CTBT and International Organizations and Agencies to address global challenges, disaster risk prevention and mitigation of natural hazards. From the CTBTO’s perspective, these synergies are envisioned in the form of International Monitoring System (IMS) data contribution to institutions that utilize data fusion platforms in order to enhance their mission. Initially, the CTBTO provided data to tsunami warning centres (the CTBTO now has a total of 18 tsunami warning agreements in 17 countries). In recent years the scope of this concept was broadened to include earthquake monitoring, volcano eruption monitoring for aviation and maritime safety, underwater acoustic anomalies monitoring, extreme weather events and phenomena, as well as detection of radioactive emission(s) and its dispersion to warn and protect citizens. The objectives of such monitoring systems are in-line with global challenges and the goals outlined in the United Nations’ Sustainable Development Goals (2030 Development Agenda), the Paris Climate Agreement, and the Sendai Framework on Disaster Risk Reduction. These links will be addressed in the panel.

Speaker: Mr Bruce Howe (University of Hawaiʻi at Mānoa, HI, USA)
• 11:30 12:30
Panel discussion on Science communication: Panel discussion Location 3 (Online)

### Location 3

#### Online

• 11:30
Communicating uncertainty among scientists, to policy makers and the public 1h

Uncertainty inherently affects every measurement and each scientific statement. This basic fact is often overlooked in communication between scientists, and even more so in the public conversation on scientific topics. Scientific results, be they the product of preliminary investigations or firmer outcomes of peer-reviewed studies, are often perceived as immutable, overlooking the fact that all findings are subject to continuous scrutiny and revision as new data or theories become available. Regional and cultural perspectives also play a role in the communication and perception of uncertainty. Failure to communicate effectively on this issue can undermine public confidence and have a direct impact on perceptions of risk, and the consequences of such misconceptions have become especially prominent in the context of the global coronavirus pandemic. In the CTBT context, uncertainty is an inescapable element of the characterization and communication of Treaty-relevant events, as well as in the framework of civil and scientific applications. This panel discussion addresses strategies for effectively communicating uncertainty when reporting about science, with the objective of delivering a clear message to audiences. It is relevant for scientists, policy makers and public information professionals.

Speaker: Mr Peter Rickwood (Atomic Reporters)
• 11:30 12:30
Series of talks on the Antropocene: Invited talks on Anthropocene Location 2 (Online)

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The idea of establishing a new geological age, the “Anthropocene’’, has created much interest globally. The Anthropocene is not a formally defined geological unit. The idea of formalizing it comes from a debate about the need to recognize a new geological age (or epoch) that is defined as having been profoundly influenced by mankind. In order to be accepted, the Anthropocene would have to be clearly visible over future geological timescales within the strata that are currently forming. Its boundary could be set by changes in geological processes such as urbanization, global warming, the agricultural impact on erosion, spreading of ocean dead zone, etc. Long-lived stratigraphic indicators such as anthropogenic pollutants including microplastics, proxies for elevated atmospheric carbon dioxide, and radioactive isotopes from nuclear testing are among a wide range of indicators under consideration. The onset of such signatures has led to a discussion on what date should be chosen for an Anthropocene boundary, with the Industrial Revolution, the advent of massive concrete structures, the use of plastics, and the start of the nuclear age being candidates. Experts at the International Geological Congress held in Cape Town in 2016 recommended that the Anthropocene epoch should begin around 1950, with the radioactive elements dispersed across the globe through nuclear explosive testing.

• 11:30
Multiple Reasons for the Anthropocene – Paul Crutzen’s Contribution to Save Planetary Boundaries 30m

The present geological epoch is now called “Anthropocene” by most scientists and increasingly by the public, largely stimulated by Paul Crutzen’s papers of 2000 and 2006 with this title. This geological epoch is not yet officially accepted, and the exact start time is debated. Whether the Anthropocene started with the steam engine in 1834, Crutzen’s proposal in 2006, or the Trinity nuclear test explosion in 1945 as proposed by the Anthropocene Working Group is rather secondary. It is clear that homo sapiens is dominating planet Earth and has already transgressed save planetary boundaries for several element cycles (e.g. carbon, nitrogen). Hence, we have to reverse the trend by global governance. As done successfully with the Montreal Protocol as part of the Vienna Convention to Protect the Ozone Layer, for which Paul Crutzen’s Nobel Prize honored research laid the foundation, and as since 2016 tried by the Paris Agreement to the United Nations Framework Convention on Climate Change. We have not only to discuss but to avoid very close tipping points of the climate system, like the complete melting of the Greenland ice sheet. To many of these scientific challenges Paul Crutzen has strongly contributed.

Speaker: Mr Hartmut Grassl (Max Planck Institute for Meteorology, Germany)
• 12:00
Artificial radionuclide fallout: a marker for the start of the Anthropocene Epoch 30m

The Anthropocene Working Group of the Subcommission on Quaternary Stratigraphy is tasked with gathering evidence to assess the Anthropocene as a potential new formal unit within the Geological Time Scale. If approved, this would be the first such unit that directly reflects a pervasive shift in the Earth System due to human activities. Evidence includes the appearance and rapid dispersal of many new mineral forms, rock types and modification of sedimentary processes. Biological evidence includes the irreversible consequences of extinctions, unprecedented species invasions and dominance of domesticated species. Recent climate and sea level trends are outside the trajectory of the previous ~11,000 years. Chemical signals include isotope patterns altered by unprecedented perturbations to the carbon and nitrogen cycles, with many disseminated metal and persistent organic pollutants forming novel signatures. Anthropogenic influence on geological signals commenced thousands of years ago, but the mid-20th century provides the most pronounced inflection in most global trends, reflecting surges in human population, energy consumption (especially hydrocarbons), technological innovation and international trade. Despite atmospheric testing of nuclear devices not being a fundamental cause of this Earth System shift, these detonations have left almost globally synchronous radionuclides traces ideal for marking the onset of the Anthropocene in multiple geological archives. This presentation details the variable nature and associated problems related to using the so-called “bomb-spike” and ongoing plans for developing a proposal for a formal “golden-spike” section in potential host environments.

Speaker: Mr Colin Waters (University of Leicester, United Kingdom)
• 13:30 14:15
Invited talks on Civil and Scientific Applications: Invited talk on civil and scientific applications Location 1 (Online)

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• 13:30
Sustainable Development, Disaster Risk Reduction and CTBTO Verification Regime 20m

Natural disasters are increasing in frequency and intensity, becoming extreme and complex and have been affecting many countries over recent years. The UN 2030 Agenda for Sustainable Development recognizes and reaffirms the urgent need to reduce the risk of disasters. The need for modern, multi-hazard disaster response systems to strengthen the national and collective ability to prevent and prepare for emergencies is evident. Early warning is a major component of disaster risk reduction with the potential to prevent loss of life and reduce the economic and material impacts of disasters. The Sendai Framework for Disaster Risk Reduction 2015-2030 recognizes the benefits of multi-hazard early warnings systems and places them in one of its seven global targets. Noting that approximately 2.5 billion USD has been invested in the CTBT Verification Regime so far, the recognition and promotion of the civil and scientific use of its data, ranging from tsunami warning to volcano monitoring, from climate change to better understanding of the ocean processes and marine life, is critical to maintain Member State and public interest and investment in this state-of-art system, even beyond Entry Into Force of the CTBT, also to preserve national CTBT verification capacity in a sustainable manner.

Speaker: Mr Ocal Necmioglu (Bogazici University, Istanbul, Turkey)
• 13:50
Civil and Scientific Applications of IMS Data 20m

Although the main purpose of the International Monitoring System (IMS) is nuclear explosion monitoring, this unique asset of available global data may also be used for scientific and civil purposes. Scientific applications follow the decision of the CTBTO PrepCom from November 2000, in which it was stated that the PTS may provide IMS data and IDC products to organizations for the purpose of conducting research associated with the development of the IMS and IDC. Since 2011, the virtual Data Exploitation Centre (vDEC) has allowed scientists and researchers access to the CTBT’s IMS data. Following the Sumatra earthquake on 26 December 2004, it was decided that national and regional tsunami warning centres recognized by IOC/UNESCO can sign an arrangement with the CTBTO to receive IMS data for tsunami early warning. After the Fukushima Daiichi nuclear power plant accident, the CTBTO became a member of the Inter-Agency Committee on Radiological and Nuclear Emergencies (IACRNE). Further civil applications for disaster risk reduction have been proposed. This presentation reviews the progress on civil and scientific applications made in the 25 years since the opening of the CTBT for signature.

Speaker: Ms Zeinabou Mindaoudou Souley (CTBTO Preparatory Commission, Vienna, Austria)
• 14:10
Discussion and questions 5m
• 13:31 15:01
Educational Initiative for Young Professionals with Technical Background: Side event
• 13:31
OSI Educational Initiative for Young Professionals with a Technical Background 1h 30m

For over a month, students of Russia’s National Research Nuclear Institute – Moscow Engineering Physics Institute (NRNU - MEPhI) have been working on case studies developed for them by the On-Site Inspection (OSI) Division. These cases cover a wide range of OSI-specific topics driven by the need to ensure its operationalization at the CTBT entry into force. At this side-event students will present their ideas and technical solutions on how to further increase the OSI capability.
For participants, it has been a unique opportunity to interact with the PTS staff and OSI experts, get a sense of what the work of the CTBTO is like and offer their take on how to address the actual challenges to one of the elements of the CTBT verification regime.
The event is organized jointly by the OSI Division, the CTBTO Youth Group Task Force and NRNU–MEPhI, that the CTBTO has traditionally close ties with, and that has been spearheading efforts to promote and enhance CTBT-related expertise and youth involvement among Russian universities and worldwide.

Speaker: Ms Anastasia Shavrova (CTBTO Preparatory Commission, Vienna, Austria)
• 14:15 15:15
Panel discussion on Civil and scientific applications: Panel discussion Location 1 (Online)

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• 14:15
Civil and scientific applications - prospects 1h

The data recorded by CTBT’s International Monitoring System constitute a unique trove of knowledge with a broad range of civil and scientific applications. In the last decade, thanks to the establishment of the virtual Data Exploitation Centre (vDEC), it became possible for international experts to have access to these data to conduct research and to publish new findings, while the organization would gain from the knowledge transfer and interaction between internal and external experts. The list of possible applications that exploit CTBT data is long and includes e.g. scientific studies on bolides, marine mammal migration studies, discrimination between earthquakes and man-made events, investigation of the Earth’s interior, investigation of source depth characteristics from large explosions or validation of atmospheric transport modelling. It includes as well civil applications, such as contribution to tsunami warning centres, the impact of ocean noise on whales, ocean thermometry and climate change.

Speakers: Mr Georgios Haralabus (CTBTO Preparatory Commission, Vienna, Austria) , Ms Jolanta Kusmierczyk-Michulec (CTBTO Preparatory Commission, Vienna, Austria)
• 15:30 16:00
Awards announcement Location 1 (Online)

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• 16:00 18:00
NDC Session: NDC session
• 16:00
NDC Session 2h

NDCs (National Data Centres) are the national technical organizations competent to advise their governments on the verification of the Comprehensive Nuclear-Test-Ban Treaty. The objective of this session is to allow NDC experts to share experience in fulfilling their verification responsibilities. During presentations and discussions, special emphasis will be put on:
• use of IMS data and IDC products for verification purposes as well as civil or scientific applications,
• use of NDC-in-a-box or specific tools in operation in NDCs,
• collaboration and interactions between NDCs.

Speakers: Several speaker interventions
The duration of each presentation is 10 minutes, following by 5 minutes of QA.