Conveners
P2.2 Seismoacoustic Sources in Theory and Practice
- Gerard Rambolamanana (Former CTBTO Preparatory Commission)
A mobile seismo-acoustic array, RAPAR (RAsPberry ARray) was constructed with six Raspberry Shake-Booms, which are relatively small and cheap equipment. RAPAR is a stand-alone equipment with geophone, acoustic sensor, digitizer, solar power supply and LTE communication system but without a wind noise reduction system. RAPAR was deployed six months in a small peninsula, Homigot, located in the...
The department of Seismology and Acoustics (RDSA) at the Royal Netherlands Meteorological Institute (KNMI) monitors seismic and acoustic activity in the Netherlands with a dense network of seismometers and infrasound sensors. An important motivation for measuring infrasound in the Netherlands is to discriminate between vibrations originating from the solid earth, e.g. earthquakes, and from the...
Infrasound data recorded with Romanian stations BURARI and IPLOR are processed and analyzed on routinely basis at NIEP by using capabilities of NDC-in-a-Box, i.e., DTK-PMCC, DTK-GPMCC and DTK-DIVA software.
This study focuses on the numerous and repeated high frequency signals (above 1 Hz) detected mainly from consistent sources related to the intense military activity caused by bombardment...
We are hosting a colossal seismic activity of the Fentale-Dofen magmatic segment to date in the main Ethiopian rift starting from September 2024. This earthquake swarm is caused by a dike intrusion beneath Fentale volcano and laterally migrating north toward Dofen volcano with a total lengt of over 40 km shown by both seismicity and InSAR data. Thousands of earthquakes with maximum magnitude...
The PS26 station was established in Niger in 2005 on a granite batholith. The PS26 data is of unrivaled quality and contributes to strengthening the verification system within the IMS. The station remains in no capable mission, but there is hope to see this station getting back within the network. In this work, we will use data from the PS26 station in order to show its contribution by...
Verification of events is a very important task for national monitoring systems. The Ukrainian NDC demonstrates this ability at least at the regional level. As an example, consider the event at the Kakhovka HPP dam that occurred on May 5, 2023. The estimated time in the source is 23:34:50 UTC. Determining the exact time of the event was accompanied by certain difficulties. First, its low...
On 26 October 2024, the Israeli Defence Forces (IDF) announced they triggered an explosion of 370 T in an underground Hezbollah facility in southern Lebanon, ~1 km off the Israeli border, generating a seismic moment equivalent to a M3.6 earthquake. Four seconds after detonation, the Geological Survey of Israel’s (GSI) Earthquake Early-Warning System, Truaa, identified the explosion as a M5.2...
On 20 June 2024, a powerful sonic boom shook the inhabitants of Elba Island (Tuscany, Italy) and was heard in a huge area on the Tuscan coast. The unknown phenomenon generated infrasonic and seismic signals which were recorded by three infrasonic arrays deployed in Elba Island (ELB), on Mount Amiata (AMT, southern Tuscany) and in Aosta Valley, and by 20 seismic stations located throughout...
Mysterious seismoacoustic events were reported at the beginning of 2022 near Helwan city. The majority of these events were recorded in our Egyptian National Seismic Network (ENSN). The source characteristics of these events were unknown. In May 2022, a temporary infrasound array station was established with a small aperture of 450 meters in Helwan. Throughout the six-month monitoring period,...
During infrastructure works in the port of Rijeka, an unexploded WWII aerial bomb was discovered at a depth of 19 meters. The bomb measured 298 cm in length, 70 cm in diameter, and weighed 986 kg, including 690 kg of explosives. Due to its size and the proximity of residential and infrastructure facilities, it was deemed unsafe to neutralize the bomb at its discovery site through a controlled...
Sometimes, powerful quarry explosions can generate an acoustic infrasonic signal, and this can be recorded on seismic sensors. The appearance of an acoustic wave can be seen on seismograms, which are calculated based on the speed of arrival of the wave. If the azimuth coincides with the azimuth of the explosion, and the speed is V=0.33 km/sec, then we can confidently say that this signal was...
Moment tensors encode seismic source mechanisms and magnitudes, providing a basis for classifying seismic events. The moment tensor is a 3×3 symmetric matrix representing three orthogonal dipoles, with their magnitudes and orientations defining the mechanism. Decomposing the tensor into eigenvalues and a rotation matrix enables analysis and classification of source mechanisms on the lune...
Since 2006, the Democratic People's Republic of Korea (DPRK) has conducted a series of six nuclear tests in the region of Punggye-ri, the latter claimed as a hydrogen bomb test, which occurred in September 2017. The estimated yield of these events ranged from 1 to 300 kilotons, based on various analyses, including seismic data and satellite imagery. The latest test was the most powerful,...
This paper presents the results of seismic data analysis related to a chemical explosion that occurred at a warehouse in Tashkent city (data 27.09.2023 UTC:21-52 ). The explosion caused significant destruction and was accompanied by the release of shock and seismic waves, which were recorded by seismological stations in the region.
The study includes an assessment of the explosion...
Uncontrolled space debris re-entries are a growing international concern, posing an increasingly greater risk on the ground as Earth orbit grows more crowded. Characterising the passage of these objects through the atmosphere is key to understanding the risks they pose, especially in evaluating whether any debris may have reached the ground. Using an example of a spent orbital module...
The Source Physics Experiments (SPE) are a series of controlled chemical explosions at the Nevada National Security Site to gather observations to verify and validate explosions' physics-based numerical models and understand the genesis of shear waves to improve nuclear discrimination and monitoring capabilities. Executed between 2011 and 2016, Phase I encompassed six collocated chemical...
An experimental infrasound array, combined with collocated seismic sensors, detected in Southern Brazil an event characterized by waves arriving simultaneously at both types of sensors. This suggests a common source for the waves, traveling at the same velocity. However, different source types could satisfy these conditions. This study analyzes signals recorded by a four-element infrasound...
T-waves are hydroacoustic waves that propagate as guided waves over long distances through the ocean, representing energy trapped in the Sounding Fixing and Ranging (SOFAR) channel. T-waves resulting from earthquakes have complex waveforms and simulations suggest that their long wavetrains are generated by scattering of upward traveling seismic energy at a rough seafloor and multiple...
A method to estimate yield and depth of explosions when accompanied by both DC and strong CLVD contributions will be presented. This paper will point out an amplitude deficiency in the CLVD green functions (GFs) constructed using no-torque three-orthogonal force dipoles (FDP). Vertically symmetric CLVD GFs are smaller by a factor of 2 than the DC source ZDD/RDD GFs, which is not accounted in...
