Seismological Society of America

Detection of Small Earthquakes by Waveform Envelope Using Machine Learning #BSSA Seismic data helps to reveal what’s happening inside Earth. In particular, bigger earthquakes produce energetic seismic waves that travel through the globe, reaching distant seismic stations and illuminating interesting and important structures along the way. However, there aren’t that many moderate-to-large earthquakes. Small earthquakes, which are more numerous and are essential for seismic monitoring, can be difficult to detect. In a new paper, scientists from University of Science and Technology of China present a #MachineLearning based detection method that catches the “waveform envelope” pattern of seismic data. This envelope captures a low-frequency pattern for any event. The approach performs well in scenarios with different signal-to-noise ratios, according to the authors, and they find that more small events can be detected. https://lnkd.in/g__jgYM9

📣 LATE BREAKING SESSION added to 2025 SSA Annual Meeting! The session on recent earthquakes including ongoing earthquake swarm near #Ethiopia and M 7.1 Southern #Tibetan Plateau earthquake is now open for abstracts, due 28 February https://buff.ly/482PZbC #seismology #earthquake

Our 5-session online course on effective scientific public speaking, slides and poster design with Ross S. Stein starts tomorrow, 14 January, but there's still time to sign up! Registration is FREE for those who have renewed their membership through 2025: https://buff.ly/44Rw2DK

Kinematics of the 2023 Kahramanmaraş Earthquake Doublet: Biased Near‐Fault Data and Shallow Slip Deficit #SRL When large, shallow, strike-slip earthquakes strike, there's usually a discrepancy between how much shallow slip is observed versus the amount of slip at intermediate depths. The strangely reduced magnitude of slip at shallow depths is called shallow slip deficit, or SSD. Understanding shallow rupture is important because movement at the surface is responsible for the more damaging surface waves. In a new #SRL paper, scientists from University of Science and Technology of China consider SSD for the 2023 Turkey earthquakes. Previous studies suggested that SSD may vary from a few percent to about 50%. The team explores just how much the ground moved compared to intermediate depths by including refined near-fault Interferometric Synthetic Aperture Radar observations. Find out more in the paper. https://lnkd.in/gYxBt4BK

📣New paper and Press Release about seismology and whales!🐋 Imaging Underwater Faults and Tracking Whales with Optical Fiber Sensing, published in #SRL Using an existing telecommunications fiber optic cable running along the sea floor, researchers identified faults and tracked the locations of whales traveling up and down the central California coast. A team of scientists from GFZ Helmholtz Centre for Geosciences, Caltech, and California Polytechnic State University-San Luis Obispo demonstrate the potential of distributed acoustic sensing, also called DAS, for visualizing the geohazards that could impact deep-water offshore wind energy projects. Understanding these hazards is essential for safe deployment of offshore wind projects, but the sea floor sediments beneath floating deep-water platforms are rarely mapped. What’s more, the techniques traditionally used to seismically map these regions—usually “active” source methods that often use loud acoustic emissions—can disturb marine life such as migrating whales. DAS offers a way to develop a high-resolution image of the top 100 meters or so of sea floor sediment while also collecting data on whale calls that can help wind energy companies avoid whale migration paths, the researchers found. Find out more in the paper and accompanying press release. paper: https://lnkd.in/gxE4C4wU press release: https://lnkd.in/gRhPp96w

Statistical Analysis of Characteristic Parameters and Probability Distribution of Near‐Fault Velocity Pulses—A Case Study on the 1999 Mw 7.6 Chi-Chi Earthquake #SRL Near-fault velocity pulses can cause severe damage to structures located near the fault rupture. These pulses exhibit high amplitude, long period and concentrated energy, and have been observed in several major earthquakes. The 1999 magnitude 7.6 Chi-Chi earthquake in the Taiwan region generated ground motion data that can facilitate the study of near-fault velocity pulses. In a new paper, scientists from China Earthquake Administration, Southwest University of Science and Technology and Shenzhen Academy of Disaster Prevention and Reduction built a source model, simulated the earthquake’s ground motions, and obtained synthetic velocity waveforms consistent with observed waveforms. Then, they explored the distribution of velocity pulses in the near-fault region. Among their findings, they note that structures with natural periods ranging from 1 to 7 seconds are more susceptible to resonance from near-fault velocity pulses. https://lnkd.in/gBr2P7VF

Learn more about how Daniel Gittins at Cooperative Institute for Research in Environmental Sciences is busy in his workshop and in the (literal) trenches studying aseismic creep in this month's SSA At Work! https://buff.ly/4fPJk8m

Assessing the Earthquake Recording Capability of an Ocean‐Bottom Distributed Acoustic Sensing Array in the Sanriku Region, Japan #SRL The oceans are sparsely instrumented when it comes to seismic stations, but distributed acoustic sensing (DAS) can help. DAS can turn existing fiber optic cables into thousands of seismic sensors. Yet, ocean-bottom DAS for routine seismic monitoring has not been explored in detail. In a new study, scientists from University of Michigan and The University of Tokyo investigate the recording capability of such an array in the Sanriku region of Japan. They compare manually selected ocean bottom DAS data with co-located ocean-bottom seismometer data. They find that the ocean bottom DAS sensors can record earthquake waveforms when an earthquake exceeds the noise level. They also propose algorithms to detect earthquakes in the DAS array, finding about 80% of the cataloged earthquakes as well as thousands of previously uncatalogued events. For more, please visit the paper. https://lnkd.in/gG5tc-fp

📣 DEADLINE EXTENDED: Deadline for #SSA2025 abstract submissions is now 14 January, due to severe weather occurrences including the ongoing fires in the Los Angeles area. Our thoughts are with everyone affected, and we hope for safety and relief for all. https://buff.ly/482PZbC

Crustal Azimuthal Anisotropy in Eastern North China Derived from Ambient Noise Tomography #SRL The North China craton has experienced lithospheric destruction and thinning since the Late Mesozoic as a result of westward subduction of the Pacific plate. In particular, the eastern part of North China is tectonically active with a history of intense magmatism, a series of fault systems, high seismicity, and complex structures. Understanding those structures and the anisotropy of the crust is of great significance for understanding what’s happening. In a new paper, a team from the China Earthquake Administration apply ambient noise tomography in eastern North China. They see significant heterogeneity in crustal velocity and anisotropy. They note that inconsistent anisotropy patterns in the crust and upper mantle suggest that crust and mantle deformation are decoupled. For a detailed discussion of their findings, please visit the paper. https://lnkd.in/gPCg62PW