Sampling of volcano seismic and acoustic wavefields have traditionally been limited to two dimensions due to the surrounding topography. However, volcano seismo-acoustic sources are known to be anisotropic and the resultant waves strongly influenced by crater morphology and topography. Between 26 July – 2 August 2016 we deployed a dense network of seismic and infrasonic sensors at the very...
An acoustic-impedance probe has been developed for the purpose of on-site evaluation of pipe-based wind-noise-reduction systems (WNRS) and microbarometers. The probe generates a controlled volume displacement using a precision graphite-in-glass piston. The displacement is measured with a linear variable-displacement transformer (LVDT) and the acoustic pressure is measured with a DC-coupled...
Signal association across the International Monitoring System (IMS) infrasound network is challenging. Several factors contribute to the difficulty in identifying events that generate multiple observed infrasound signals across the IMS including: the sparseness of the network, the variability in signal propagation speed (celerity), and the lack of signal characteristics that contain...
The ability of the International Monitoring System (IMS) infrasound network to detect atmospheric explosions and events of interest strongly depends on station specific ambient noise which includes both incoherent wind noise and real coherent infrasonic waves. To characterize the coherent ambient noise, a broadband array processing was performed with IMS continuous waveform archive from 2007...
Kenya hosts two IMS stations and several seismic station network Having endured, and,after fully addressing the life cycle challenges at both of these stations,we have now embarked on the civil and scientific application of data that is collected by both these stations and sent to both the IDC in Vienna and the NDC-KE in Kenya. The involvement of the government, the local community and the...
Ground networks to monitor geophysical processes such as climate change variability and its outcomes such as lightening are inexistent in Uganda. Recently good progress is being made in decision making. Implementation of good decisions can solve negative outcomes of natural processes and can be mitigated to avoid destruction of property and loss of life using science and technology based...
The Tengchong seismo-acoustic array located in southwest of China has been running for 5 years. We perform broadband (0.01–5 Hz) array processing with the infrasound continuous waveform data (from 1 January 2011 to 31 December 2015) using the Progressive Multi-Channel Correlation algorithm in 15 log-spaced frequency bands defined by Matoza et al.(2013).The detection results show microbaroms...
Detection capability of infrasound arrays is complex to assess. It is dramatically affected by the background noise, the propagation medium, the array configuration, as well as the type of algorithm used. The completion of IDC event bulletins requires that software be tuned to detect wide variety of signals in broad and well separated frequency bands, often buried in the background with low...
Sensor self-noise may be defined as the output signal from the sensor in the absence of an external stimulation. Typically this is measured using sealed instrument ports, and ideally in a chamber with significant environmental isolation. Such a measurement is referred to as a “static self-noise measurement.” It is also possible to apply a known signal to the sensor being tested, and obtain an...
Infrasound Technology is a vital element of the CTBTO’s International Monitoring System (IMS) which monitors the globe for compliance with the Nuclear Test Ban Treaty. Understanding this technology and knowing how it works is very critical to the overall performance of the IMS and indeed eventual entry into force of the Treaty. Connecting the public has been a major step taken by the CTBTO to...
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...
IMS Infrasound Station IS41 “Villa Florida Paraguay” was installed and certified in 2003 is operated by the National University of Asuncion. During the last years the station started to experience several technical problems and data transmission to Vienna was interrupted from weeks to months resulting in station non capability. Anyhow Paraguay NDC with IMS data and IDC products focus on the...
Researchers can benefit from designing and building custom instruments, achieving greater convenience at a lower price. As an example, we present an infrasound logger (named the Gem) designed specifically for campaigns on volcanoes. Unlike commercial alternatives, the Gem is inexpensive, specialized for volcano fieldwork, and user-serviceable. It has a fraction of the per-channel cost of other...
This year, NASA’s Near Earth Object Program reported a 13kt bolide at 13:55 on 06- February-2016 and at 31km above the South Atlantic (30.4◦S, 25.5◦W). Only two IMS stations, both in Antarctica (IS27 and IS55), automatically detected arrivals from this event. These stations are ∼4600 and ∼8000km from NASA’s location, respectively. The arrivals were not automatically associated and are in the...
A large explosion occurred in Tianjin Port, China on 12 August 2015, as a result of an ignition of hundreds tons of explosive material (ammonium nitrate). The explosion generated large amplitude infrasonic signals that were recorded at range of 3.5km-800km. We present an analysis of data using 7 infrasound stations and 3 seismic stations. The infrasound station TJB recorded the infrasonic wave...
I. H. Hamama , M. N. ElGabry, H. M. Hussein National Research Institute of Astronomy and Geophysics, 11421 Helwan, Egypt . Infrasound is one of the most important technology which used in detection of surface nuclear explosions. The very low frequency of sound waves are still the secret to detect very far objectives, surface explosion In the early morning of 7th of October 2008, infrasound...
Researchers at the Sandia National Laboratories Facility for Acceptance, Calibration, and Testing (FACT) site have been working to expand capabilities for the evaluation of infrasound sensors. These capabilities include an improved infrasound isolation testing chamber and expanded field sites with an installed infrasound array. The new infrasound chamber improves upon the isolation of the...
Infrasound stations on free floating balloons suffer little wind noise, are entirely decoupled from ground vibrations, and have a greatly extended detection range compared to those on the ground. Despite the potential advantages of such stations, few studies have addressed the research and operational opportunities afforded by free flying sensors. The last three years have seen several...
Abstract Infrasound Experiment in Indonesia Hendri Subakti Scientific collaboration between the BMKG and the CEA in the field of geophysics started in the 1980’s, and more recently in the field of infrasound with the installation of the experimental station in Palangkaraya Borneo and Pelabuhan ratu Java also Tondano North Celebes. The volcanic activity is very important in Indonesia where...
A single infrasound sensor has been making continuous recordings since 2008 at Syowa Station (SYO; 69.0S, 39.6E) in the Lützow-Holm Bay (LHB) of East Antarctica. The continuously recorded data clearly show the contamination of background oceanic signals (microbaroms) throughout all seasons. In austral summer 2013, several field stations with infrasound sensors were established along the coast...
The IS08 was certified on 20 August, 2002 and IS17 on 9 December, 2002. IS08 contributed recorded data in the study of the earthquake that occurred in Ecuador on 16 April, 2016 while IS17’s data was used for the earthquake of 12 August, 2010. The data from these two infrasound stations coupled by that of seismic stations were used to locate both events. This study presents the station...
Infrasound technology has been developing rapidly in the last 15 years and is now reaching a level of maturity that justifies deploying infrasound stations for monitoring geophysical phenomena. Infrasound stations are being deployed worldwide, for both scientific and societal applications. BMKG and CEA have extended their collaboration to set-up experimental infrasound stations across the...
We use infrasound waves generated by volcanic eruptions at Volcan Tungurahua to study both changing atmospheric conditions and source characteristics. Analyzed infrasound data were recorded for a 32 month period at Volcan Tungurahua by a five-station network (within 6.5 km from the vent). We use cross-network correlation to quantify the cyclic eruptive behavior of Tungurahua and results are...
We have investigated the effects of stratospheric winds on the amplitudes of atmospheric nuclear explosion infrasound signals for distances up to 17500 kilometers. The raw amplitudes data set were scaled for yield. We extracted the zonal and meridional winds from source to receiver propagation path using the Horizontal Wind Model (HWM14) database. An attenuation propagation constant k is...
While planning the installation of IS01 with the Provisional Technical Secretariat (PTS) late 2015, the Autoridad Regulatoria Nacional (ARN) proposed a plot of land roughly 60 km to the east of Bariloche, Argentina for the station installation. Having been given a set property boundary, the PTS worked to design an optimal array geometry before performing the site survey. As part of a joint...
Studying the propagation of a waveform throughout a given atmosphere, numerically or theoretically, requires knowledge of wind speed and temperature gradients. A consensus has emerged that the main part of small-scale fluctuations is filtered out of the available data, even though it is known that these fluctuations significantly alter the determined propagative path of the waveform. In most...
Wide global infrasound coverage is obtained using the CTBTO land-based sensing network, whose primary purpose is to detect nuclear test explosions. However, two thirds of the earth’s surface is composed of oceans, and no capability yet exists to monitor infrasound signals from sensors fielded in the maritime environment, for example, as hosted by ships, ocean buoys or Unmanned Surface Vehicles...
The Multiple Signal Classification (MUSIC) algorithm (Schmidt, 1986) is a well-known high-resolution method used in array processing for parameter estimation. We report on the application of MUSIC to infrasonic data at frequencies applicable to the regional and global explosion monitoring. The infrasonic wavefield is comprised of multiple sources (e.g., microbaroms, anthropogenic noise, mine...
The results of infrasound waves propagation modeling for Chelyabinsk meteoroid explosion on February 15, 2013 using the pseudodifferential parabolic equation are shown. The estimation of the explosion location was conducted by analysis of seismic recording near the epicenter. The IS31 located 542 km away of the explosion has recorded 6 infrasound arrivals. The first infrasound arrival from a...
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...
The ASHE Ecuador (2004-2012) collaboration between Ecuador, Canada, and the US demonstrated the capability to use real-time infrasound to provide low-latency volcanic eruption notifications to the Volcano Ash Advisory Center (VAAC) in Washington DC. The Atmospheric dynamics Research Infrastructure in Europe (ARISE, 2012-2018) supported by the European Commission fosters integrating innovative...
The National Data Centers established around the globe with the support of the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) are used to monitor and manage its data, to control and ultimately eliminate nuclear weapon test explosions. The National Data Center in Ghana was established six years ago to support this course. The Center’s mandate is to collate seismic, infrasound,...
Previously, no US-based facility existed for year-round testing and evaluation of infrasound equipment and designs in the field. The US Nuclear Arms Control Technology (NACT) R&D Testbed at the Sandia National Laboratories (SNL) FACT site has therefore been designed so infrasound equipment and designs can be tested in a realistic environment before they are deployed at IMS stations. In March...
IMS Infrasound stations detect mostly signals from Mountain Associated Waves at frequency range [0.015 - 0.1Hz]. MAWs are generated as hydrodynamic oscillation in the turbulent wind-stream in the lee of high mountain ranges (Meecham, 1971). Drakensberg mountain located in SouthAfrica is used as source for studying the amplitude attenuation (Bass & Sutherland, 2003) at two infrasound stations...
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...
A massive explosion in Tianjin erupted at a container port where flammable material was being stored. The explosion produced a mushroom with great shock waves that attenuated gradually and degraded into infrasound in far range. The infrasonic signals were registered by several IMS and domestic infrasonic stations several kilometers away. The signal detection algorithms based on slowness...
The theory of the infrasound wave propagation states that the acoustic waves of infrasound sources, related with wind and temperature conditions, can be detected at the distance between 200 km and 250 km (McKenna, 2005; Golden et al., 2007). From our seasonal infrasound observations (winter and summer monitoring) and research studies, we would to understand that why some seismo-acoustic waves...
Kazakh infrasound network will consist of three arrays: IS31 Aktyubinsk, Kurchatov and Makanchy when the last one will be opened. Russian infrasound station IS46 Zalesovo is close to our network and its data also may be used for the network processing. There are no many places all over the World when concentration of the infrasound station is the same high. Kazakh NDC automatically detects...
Seismoacoustic effects of the Khubsugul earthquake of December 5, 2014 (51.37N, 100.63E, MW=4.9) were studied. Earthquake occurred in the Khubsugul basin at the depth 3 km. Acoustic signal was registered by the infrasound station “Tory” located at the distance 175 km from the epicenter. Travel time of acoustic waves is about 280 s. Apparent velocity of infrasound signal propagation is ~625...
Volcanoes are efficient sources of infrasonic waves that can travel large distances (>1000 km) in atmospheric waveguides with very limited amplitude loss. In favourable propagation conditions, long-range infrasound well tracked the occurrence and the duration of volcanic eruptions: yet, the potential of infrasound technology to infer the fine details of the volcanic eruptive source is still...
Long-range infrasound propagation problems are characterized by both a large number of length scales and correlatively a large number of normal modes. In the atmosphere, these modes are confined within waveguides causing the sound to propagate through multiple paths to the receiver. Even though the accuracy of atmospheric specifications is constantly improving, the main part of gravity waves...
Until 2003 two waveform technologies, i.e. seismic and hydroacoustic were used to detect and locate events included in the International Data Centre (IDC) Reviewed Event Bulletin (REB). The first atmospheric event was published in the REB in 2003, however automatic processing required significant improvements to reduce the number of false events. In the beginning of 2010 the infrasound...
The ability of experts from the emerging NDCs to posses the capability for utilization of the data and products from all the verification technologies constitutes a major step towards the overall success of the CTBT implementation. Currently, there appears to be indicative of serious human and institutional capacity inadequacy within several countries in the West African sub-region in the...
There are six IMS infrasound stations (IS02, IS08, IS09, IS13, IS14 and IS41) which cover the continental shelf and territory of South America. Two major earthquakes on March 23, 2015 and September 16, 2015 occurred within the territory of Chile that lies within the area covered by these infrasound stations. Using these infrasound stations coupled by seismic stations the two events were...
In this study, some local networks of Iran are presented and their activity compare with regional networks are shown emphasizing the remarkable natural difference of seismic activity detection. 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 instruments could be a useful mean while going...
The analysis of local and regional sources of infrasound emission was done using the new software DTK-MCSP and DTK-DIVA provided by the CTBTO. The sources were studied in 2009-2016.
The analysis showed two (2) frequency bands emission from these sources: 3.0-1.0Hz and 0.3-0.1Hz respectively for high and low frequencies. The different sources detected can be divided into two (2) groups...
To date, the Ukrainian infrasound observations network requires global modernization and technical re-equipment. To create conditions for compliance with the international practice, Ukrainian NDC plans to carry out work related to improving the characteristics of the two infrasound arrays. The first phase will be significantly expanded arrays aperture and improved characteristics of a noise...
Propagation-based, stochastic models for infrasound signal analysis were recently introduced in the context of event localization with promising results. Models for celerity‐range and azimuthal variations due to cross winds have been shown to produce improvements in the accuracy and precision of infrasonic source localization estimates. Following this approach, propagation‐based, stochastic...
New methods for estimation the energy of explosions by registration data of infrasound waves are proposed. The one method is based on using acoustical impulse I conservation law - E(I)[kt]= 1.38x 10^(-10)(I[kg/sec])^1.482. Where I is the result of a multiplication wave profile area S/2 of analyzing infrasound signal by a distance to the source. The second method uses correlation between an...
Burkina Faso NDC and IDC have worked in the field of seismic and infrasound to conduct investigations of various catastrophes. That's how we carried out investigations into the Ouagadougou explosion and Air Algeria crash respectively on 15 and 24 July 2014 and which allowed us to locate them. In recent years, various studies demonstrate the use of technology valuable infrasound as a complement...
National Institute for Earth Physics operates Plostina six-element infrasound array (IPLOR), as well as the dense Romanian Seismic Network (RSN) (over 100 stations). As a result of its sensors' type (Chaparral Physics Model 25) and large aperture (2.5 km), IPLOR array has proven effective in detecting acoustic signals produced by near-field impulsive seismoacoustic sources such as atmospheric,...
In infrasound propagation modeling, we often face a large number of potential atmospheric models with only a limited number of recorded signals to conduct inference from. Prediction of acoustic signals is a complex issue due to constantly changing atmospheric conditions and to the random nature of smallscale flows (turbulence, gravity waves). Thus, the uncertainty over which model to use for...
