Large, passive wind noise reduction systems are of great interest to the infrasound community. Recently, several different designs were built and tested in order to quantify their effectiveness in reducing wind noise while maintaining acoustic waveform fidelity in the frequency range of interest to the monitoring community. The designs include large perforated aluminum domes, domes constructed...
Phase I of the Source Physics Experiment (SPE) was a series of six underground chemical explosions in granite. The experiment focused on improving the nuclear explosion monitoring community’s understanding of the seismo-acoustic signatures of buried explosions. We discuss the amplitude, impulse, and peak frequency of each shot with respect to explosive yield and depth of burial. We describe a...
Kazakh infrasound network consists of tree arrays: IS31 at the west of Kazakhsatn, Kurchatov at the north-east and Makanchy at the east. Kazakh NDC also processes the data of the neighbor IS46 array, Altay, Russia. North Kazakhstan and neighboring part of Russia have got very high mining activity. Signal detection and its source location is automatically performed at Kazakh NDC since June...
The planetary evolution and structure of Venus remain uncertain more than half a century after the first visit by a robotic spacecraft. To understand how Venus evolved it is necessary to detect potential signs of current seismic activity. Due to the adverse surface conditions on Venus, with extremely high temperature and pressure, it is infeasible in the near future to place seismometers on...
Andøya Space Center (ASC) is a well developed research infrastructure for atmosphere science and related research fields. Since 1962 ASC is a service provider for sounding rockets and in parallel we build-up a comprehensive ground based infrastructure of atmospheric radars, lidars and passive ground based instrumentation. Through a project within H2020 new research on the dynamics of the...
The IS17, DBIC and TORD stations are all within 1000km from the Tongon open pit mines which are located in the north of Côte d’lvoire, 55km south of the border with Mali. The ability of these stations to be deployed for civil and scientific purposes was assessed from July 2016 to March 2017 with the study of mining activities that occurred at Tongon. Using IMS data and IDC products in the...
Infrasound monitoring is one of the four Comprehensive Nuclear-Test-Ban Treaty (CTBT) monitoring technologies globally deployed by the Provisional Technical Secretariat (PTS) to continuously monitor the planet for signs of nuclear explosions in the atmosphere or shallow underground. There is continuous interest by the PTS to enhance its capability in acoustic source detection, localization and...
Calibration is an essential process to ensure data quality and trustworthiness. As defined in the IMS Operational Manual, it encompasses two distinct processes: "initial calibration" and "on-site calibration". When an infrasound measurement system is to be deployed at an IMS station, specification data provided by the manufacturer for each individual piece of equipment are first reviewed to...
Argentina has adopted the CTBT and fully ratified in December 1998. Since the beginning, ARN was designated responsible for the RN and IS technology of the International Monitoring System (IMS).In this sense, ARN and Provisional Technical Secretariat (PTS) started working together towards the installation of the stations under Argentina responsibility. IS02 Ushuaia station became operational...
The ability of the International Monitoring System (IMS) global infrasound network to detect atmospheric explosions and events of interest strongly depends on station specific ambient noise signatures which include both incoherent wind noise and real coherent infrasonic waves. To characterize the coherent ambient noise, broadband array processing was performed on 10 years of continuous IMS...
First infrasound station I34MN was installed in 2002 in Mongolia. Since that the acoustic signals have been continuously being registered with seismic signals from mining blast and determining the source parameters. In the winter time we continuously detect mining signal from Baganuur blast (150 km from mine) but we did not register any signal in Summer time. That was not in agreed with ground...
Seismic and acoustic sensors record background noise that is a superposition of different wavefields that originate from sources distributed in space and that arrive at such sensors simultaneously (e.g.: ocean noise and anthropogenic noise). Event detection can be improved through mapping these sources and their spatio-temporal evolution with historical data that includes effects of persistent...
Recent experiments with balloon-borne infrasound sensors suggest that they have lower noise levels and an increased signal detection range compared to ground based microphones. They can also travel over regions that lack station coverage, such as polar regions and the open ocean. However, current designs cannot determine the arrival azimuth of incident signals and cannot maintain a constant...
Presented here are three seismoacoustic catalogs from various years and locations throughout Utah and New Mexico. To create these catalogs, we combine seismic and acoustic events detected and located using different algorithms. Seismoacoustic events are formed based on similarity of origin time and location. Following seismoacoustic fusion, the data is compared against ground truth events....
The aim of this study is to assess the current status of IMS infrasound network in order to monitor the Eurasian Arctic region and analyse the geographical distribution of infrasound events based on the Late Event Bulletin (LEB) at the CTBTO. The study area covers several provinces of the Eurasian Arctic such as Fennoscandia, North-Western Russia and adjacent territories. In total over 500 LEB...
The IDC advances its methods and continuously improves its automatic system for the infrasound technology. The IDC focuses on enhancing the automatic system for the identification of valid signals and the optimization of the network detection threshold by identifying ways to refine signal characterization methodology and association criteria. An objective of this study is to reduce the number...
Number of distortions can affect the data quality of infrasound records. Remote diagnostics of infrasound stations in the area of signal quality includes analysis of power spectral density plots (PSD) of the remote elements. In the presentation we try to summarize the most typical signal distortions which are visible in the PSD, with source explanation and recommendation for remedial actions....
At the time of the 2011 off the Pacific coast of Tohoku Earthquake, several microbarographs around focal region recorded pressure changes excited in tsunami source region. After that, Japan Weather Association(JWA) have started experimental infrasound observation at two stations in Ofunato city and Shima district to study infrasound monitoring technique for detection of large tsunami...
Polar lows are short-lived, but intense, small-scale extreme events which can develop quickly over polar waters. The development and tracking of these mesoscale cyclones is challenging to predict and monitor, while their high intensity may represent a significant hazard to Northern sea activities. Infrasonic tracking of polar low systems was reported in Ørbaek and Naustvik's pioneering work...
International Monitoring System (IMS) Infrasound network is a state of art network of sensors that records several acoustics sources, Waves generated by anthropogenic atmospheric source ranging from regular air traffic, subsonic signals, rocket lunch are usually recorded by the IMS Infrasound stations. Interestingly Rocket lunch and re-entry acoustic signatures are recorded by IMS. These...
Long-range infrasound propagation is characterized by large variances due to factors such as stratospheric jet variability, turbulence, and the fact that the atmospheric specifications fail in representing small-scale fluctuations. In numerous situations, the atmospheric ducts are poorly formed, in the sense that they just barely return sound to the ground. In such cases, the proper numerical...
Bogoslof is a submarine stratovolcano in the Aleutian Arc with a shallowly submerged vent that results in abundant seawater interaction during eruptions. Most of the 63 significant explosive events have been recorded on the Alaska Volcano Observatoryâs infrasound arrays that range from 60 to 800 km from Bogoslof. The events have been dominated by low frequency energy (0.067-1 Hz), with...
Infrasound isolation chambers are used to isolate sensors from ambient conditions in order to perform calibrations of the sensors being evaluated. Calibrations are typically performed on sensors to be deployed within a monitoring station. Calibrations identifying that a sensor meets performance requirements are necessary before a station can be certified for inclusion within the International...
With the advent of Civil Aviation and the exponential growth in the air traffic the problem of a volcanic ash encounter has become an issue of paramount importance, which needs to be addressed in real time. We discuss the contribution of the ARISE project to volcano monitoring and to Volcanic Ash Advisory Centers (VAACs) and highlight the need for an integration of the CTBT-IMS Infrasound...
Infrasound research in Madagascar started since the installation of I33MG in 2001. At that time, only data from this station were processed. Starting from 2010 Madagascar got access to IMS data and IDC products, and then after Madagascar NDC received the Capacity Building System, infrasound data from other IMS station was accessible and easily processed. Infrasound data from IMS stations...
The Infrasound Station I09BR, located in Brasilia, Brazil, was installed in 2001 and has been in operation to this date with four elements of 18m WNRS. The station has some data quality issues and is undergoing major maintenance works planned to be finished in 2018. Until now, the team at the Seismological Observatory of the University of Brasilia actively worked to maintain the station within...
Inaudible sound, i.e., infrasound, is generated by glaciers while moving and cracking and during calving events. Such sounds can be continuously monitored with microbarometer arrays. Changes in the rate of events can be retrieved with a resolution of a few seconds. Applying array processing techniques enables the identification of individual sources over ranges of tens, in this case, to...
Some local networks of Iran are presented and their activity compare with regional network. Seismic networks are and will be probably forever the only tool that enables study of the detailed structure and physical properties of the Earth. Local seismic networks could effectively use checking seismic activity of any area with highest resolution and precision. Lots of small events couldn’t...
We are developing methodologies for automated remote detection, location, and source characterization of volcanic infrasound. The two major sub-plinian explosive phases of the 22–23 April 2015 VEI 4 eruption of Calbuco volcano, Chile produced powerful infrasound. The eruption was recorded on regional seismo-acoustic stations out to 1,540 km and on 5 stations (IS02, IS08, IS09, IS27, and IS49)...
Estimating the direction of infrasound signals over arrays usually utilizes similarity between waveforms on neighbouring sensors to measure time-delays accurately. Estimate quality can suffer due to diminished coherence over the full array aperture and methods such as PMCC exploit the increased similarity between signals on the most closely-spaced instruments. It is often helpful to examine...
Wide infrasound coverage is obtained using fixed, land-based monitoring stations. However, two-thirds of the earth’s surface is composed of oceans, and while some sensing stations are located on islands, no capability yet exists to monitor infrasound from sensors fielded directly in the maritime environment. We investigate the potential of fielding of microbarometer sensors in the maritime...
There is presented a set of instruments for calibrating of measuring instruments adapted for measurements in infrasound frequencies range and the technique of their practical application. There has been a lack of such devices so far, combined with a slight feeling of need for calibration of the measuring equipment by acoustic methods. The instrumentation has been developed in response to the...
The results of acoustic sounding of the lower troposphere by using detonation generators of acoustic pulses are presented. Such sounding method is based on a partial reflection of the acoustic pulses with shock fronts from vertical wind-velocity and temperature gradients continuously varying with height in the troposphere, and on the penetration of reflected signals into the acoustic shadow...
The IS35 Infrasound station in Tsumeb Namibia has been operating since 2005. The Namibian NDC is located 400km away from the infrasound station and is managed by the sub-Division, Crustal Geophysics, in the Geological Survey of Namibia. High staff turnover was primarily due to lucrative salary improvements in the private sector, however with a significant slump in the mining sector in recent...
In the South-West Indian Ocean, tropical cyclones occur every year from December to April. As they move, cyclones generate swells that may represent infrasound sources (microbaroms at 0.2 Hz) and sources of microseismic noise(secondary peak, 0.1-0.35 Hz). A dominant source of noise in the oceans is issued from interaction of two swells of similar periods propagating in opposite directions....
The last two decades witnessed a dramatic increase of scientific interest for infrasound technology: since the establishment of the CTBTO Preparatory Commission and the progressive development of the International Monitoring System (IMS) Network. The infrasound component of the IMS Network (completed by 82%) largely demonstrated its potential for the detection of a variety of man-made and...
In Costa Rica we currently have a volcanic seismic network of around 60 volcanic seismic stations, permanent GPS stations and gases stations in active volcanoes of Costa Rica, such as Rincon Vieja Volcano, Turrialba Volcano, Irazu Volcano and Poas Volcano. We want to include the Infrasound technique to correlate it with data from seismic stations and volcanic video surveillance systems. The...
In this study we are going to present results of global coherent infrasound noise field measured at IMS infrasound stations and its correlation with atmospheric dynamics. A new implementation of the Progressive Multi-Channel Correlation (PMCC) algorithm has been used, which enables a better characterization of all received signals in their wave parameter space (e.g., frequency-azimuth space,...
The accuray of propagation modeling depends in large part on the reliability of both the medium and the boundary conditions. In order to incorporate topography effects in infrasound propagation, high-resolution terrain models are used through approximating the lower boundary by a sequence of up and down stair steps. This simplified approach may also be viewed as applying a "mask" onto the...
Numerical prediction of infrasound is a complex issue due to constantly changing atmospheric conditions and to the random nature of smallscale flows. Although part of the upward propagating wave is refracted at stratospheric levels, where gravity waves significantly affect the temperature and the wind, yet the process by which the gravity wave field changes the infrasound arrivals remains...
A better localization of infrasound events in West Africa and on the African equatorial band requires fairly close infrasound station data. This improvement of localizations is possible due to the zonal organization of altitude wind jet over this region. In Africa, Côte d’Ivoire has an infrasound station (I17CI) certified by the CTBTO since 2002. The few existing infrasound stations in this...
Since 1996, Ukraine operates a scientific station in Antarctica. The station is called Academic Vernadsky and it is located on Galindez Island, 7 kilometers from the shoreline of the Antarctic Peninsula. In 2001, on the station was installed a seismoacoustic complex of equipment for studying geophysical processes and climate. This complex consists of a three-component seismograph and one...
PTS portable infrasound array (I67RO) has been deployed in western Romania for one year, starting with late September 2016, within a collaboration project between National Institute for Earth Physics (NIEP) and PTS of the Preparatory Commission for CTBTO. The four-element array of 0.9 km aperture is equipped with CEA/DAM MB2005 microbarometers and Reftek RT 130 data loggers. Currently, I67RO...
While long-range infrasound propagation modeling is a useful tool in nuclear treaty verification, the inherent unpredictability of subgrid-scale atmosphere dynamics results in a poorly constrained propagation medium. When faced with such a situation it is natural to treat incomplete knowledge within a probabilistic framework and to seek a numerical approach that describes long-range...
We present an analysis of infrasound events that could be performed by the paraguayan National Data Center (NDC); equipped with a Capacity Building Center (CBS), supported by AutoDRM and using GeoPMCC software to analyze the waveforms. This mentioned software comes included in the NDC in A Box. As an example, we take is41 as main station in a registration period from October 2016 to June 2017,...
Complex frequency response is a critical function in understanding the impact of a transducer on a measurement. For an acoustic transducer, a single volts-per-pascal value is often cited as the response; however, the magnitude and phase of this ratio over the entire frequency range of interest is required to understand the effects of that transducer on broadband waveforms. While this ratio can...
The PTS Midterm Strategy (CTBT/PTS/INF.1249) defined for the 2014-2017 time period underlines for the infrasound technology the importance of ensuring data quality at both the station and network levels in order to maintain and improve the capability to detect events relevant to the CTBT. This includes the use of accurate and regularly calibrated measurement systems as specified in the draft...
The infrasound network of the International Monitoring System (IMS) designed for the verification of the Comprehensive nuclear-Test-Ban Treaty includes 60 stations located around the world. Four of them are part of the Russian IMS segment: IS43 (Dubna), IS44 (Petropavlovsk-Kamchatskiy), IS45 (Ussuriysk), IS46 (Zalesovo). All Russian Infrasound IMS stations are certified and transmit data to...
A sequence of moderate and strong earthquakes is recorded by infrasound arrays up to an epicentral distance of 750 km. Two distinct signals originating at the earthquake source are detected; (1) Seismic, consisting of body and surface phases, and (2) Infrasound. However, using array processing, a third type of signal can sometimes be detected. This signal arrives after the seismic detections...
The Earth’s upper atmosphere is a dynamic region affected by both forcing from below and above. A number of processes on the Sun is resulting in eruptions of electromagnetic radiation on a number of wavelengths, and the acceleration of charged particles embedded in electromagnetic fields. The resulting space weather around the Earth shows great variability, and in this presentation we will...
A desirable adjunct for infrasound arrays in the International Monitoring System is remote diagnosis of data quality. In-situ comparison measurement provides an unparalleled degree of diagnosis for infrasound-array elements; however, this method requires either a visit to the station or installation of a permanent reference sensor at each element. A technique that uses only the normal array...
Previous airborne measurements have been done in 2014 and 2015 over the southern United States, leaving the question of stratospheric infrasound in the rest of the world open. This provides an opportunity to listen for infrasound above the Arctic Circle in an area with a developed network of ground stations, which will be used to compare with the stratospheric results. Infrasound, temperature,...
Super wide angle time domain parabolic equation code to modelling of acoustic signals propagation in different media: sea water, bottom sediments and atmosphere and their combinations are proposed. The new super wide angle version of the TDPECode based on the pseudodifferential parabolic equation technique. The numerical calculations are made for sound rays with grazing angles till to 87...
At ~19:50 UTC on 02-June-2011, the first explosion in a cannonade over a period of four hours occurred at a munitions depot near Izhevsk, Russia. Nine events are reported in the REB: six are seismo-acoustic events and three are infrasound-only. Analysis of these results has implications for IDC processing in three key areas: 1) detections - the importance of whether auxiliary data are...
IS42 is located in the Azores islands, in the middle of the North Atlantic and is one of the International Monitoring System (IMS) infrasound stations. Within the ARISE2 project, University of Azores and University of Florence (UniFi) are carrying out a collaborative research focused on the long-range detection and analysis of infrasound from volcanic eruptions at Etna Volcano recorded at IS42...
The Research Centre for Astronomy and Earth Sciences of Hungarian Academy of Sciences joined to the ARISE2 project in 2016. This year we received national funding for the deployment of an infrasound array in Hungary. After a long preparation process the array started its operation in Piszkés-tető on 1st June 2017. The Piszkés-tető Infrasound array (PSZI) consists of 4 elements, all equipped...
Bolivia has four seismogenic sources, shallow (from 0 to 75km), intermediate (from 100km to 300km), deep (from 350km to 600km) and far away sources (south of Peru and north of Chile) due to the seismic waves amplification under the main capital cities (La Paz, Cochabamba, Oruro, Santa Cruz), the earthquake of 1st April 2014 at 23:46:47 UT 8.2mww located at northern cost of Chile was felt with...
The infrasound component of the International Monitoring System (IMS) is composed of sixty stations. Forty-nine of them are already certified and transmit data in near real-time to the International Data Centre, Vienna, Austria. Each infrasound station is composed of an array of infrasound measurement systems capable of measuring micropressure changes produced at ground by infrasonic wave...
Aerodynamic noise from the continuously growing number of wind turbines in Germany creates increasing problems for infrasound array measurements recording acoustic signals at frequencies below 20 Hz. Ten years of continuous data (2006-2015) from the 4-element infrasound array IGADE in Northern Germany are analysed to quantify the influence of wind turbine noise in terms of enhanced amplitude...
Infrasound monitoring plays a vital role in the detection of signals and determining the location and size of their source.There are several factors affect infrasonic detections namely the variations in atmospheric temperature and wind speed as well as the geographical location.The infrasound signals occur through a change in atmospheric pressure above the epicentre area and are spread across...
Over the years, the ability of Researchers and other experts from across the globe to participate in the effective utilization of Infrasound Data and products is limited by the access to these data and products . The ability to constitute a major step towards the overall success of the CTBT implementation and its universalization is hinged on the greater involvement of the relevant...
The Infrasound Station IS48, in Kesra, Tunisia is part of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty. IS48 is managed and maintained by the Tunisian NDC. Its good location in the middle of the Mediterranean Sea allows to have various and interesting detections. Several signals with different signatures were recorded and identified. But since 2010, the performance of...
The main aspect of uncertainty quantification that is studied in infrasound research community is propagation of atmospheric uncertainty, which is due to the random nature of small-scale flows (e.g. gravity waves). A simple approach to this problem is to use Monte Carlo sampling, which involves a large random sample of plausible atmospheric specifications from a given distribution. However,...
Here we report on updated testing at the US NACT R&D Testbed Infrasound Array at the Sandia National Laboratories (SNL) FACT site. Rosette and polyethylene hose (HDPE) wind noise reduction systems (WNRS) were co-located at multiple elements in 2016. The long- and short-term frequency response of the two WNRS and associated sensors are compared using the in situ response technique. The...
On 25/04/2017, Burkina Faso NDC found an extremely rare event that occurred in the Atlantic Ocean northwest of the Ascension Islands near the West African coast (943 km Monrovia Liberia), a non-seismic zone . What led us to conduct a study on this event in order to know exactly what is happening in the area. This is how, we used seismic and infrasound data and also referred to the IDC REB and...
For users of ensemble weather forecasts, a key metric of forecast success is its ability to effectively predict the uncertainty of a given weather condition happening at some point in the future. Knowledge on the quality of the forecasting system is essential. Evaluation methods of forecast performance focus predominantly on the surface and troposphere. However, knowledge on the stratospheric...
As infrasound research interests move to lower signal-to-noise ratio (SNR) signals, it is necessary to enhance detection capabilities, particularly in noisy environments. The application of an adaptive F-detector has successfully reduced false detection rates attributed to coherent noise across array elements; however, the detector is applied post-processing after analysis using a standard...
