Seismological Society of America

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Commenters who post any of these types of comments may be permanently banned from the SSA page.

Linear and Nonlinear Site Responses Revealed by Single‐Station Time–Frequency Analysis: Application in Southeastern Türk...
06/20/2026

Linear and Nonlinear Site Responses Revealed by Single‐Station Time–Frequency Analysis: Application in Southeastern Türkiye

Seismic waves from the February 2023 southeastern Turkey earthquakes revealed complex local amplification, underscoring the importance of understanding site effects — how seismic waves are affected by the site at which they are felt or measured.

In a new study, scientists from GFZ Helmholtz Centre for Geosciences, Université Gustave Eiffel and the Universität Potsdam present a detailed regional assessment of site effects from seismic recordings across southeastern Turkey. They found that compared with Japan—a country with an important site where nonlinear site effects have been studied in detail—southeastern Türkiye appears more susceptible to frequency shifts under strong ground motion.

https://pubs.geoscienceworld.org/ssa/bssa/article/doi/10.1785/0120250246/730573/Linear-and-Nonlinear-Site-Responses-Revealed-by?utm_source=facebook&utm_medium=social&utm_campaign=papers

Variability in Performance of a Machine Learning Seismicity Catalog: Central Italy, 2016–2017 Machine learning-based e...
06/19/2026

Variability in Performance of a Machine Learning Seismicity Catalog: Central Italy, 2016–2017

Machine learning-based earthquake catalogs, compared to routinely compiled catalogs, contain many more events. How can we evaluate the performance of machine learning catalogs in both phase picking and earthquake detection?

In a new paper, a team from Stanford University and INGV Istituto Nazionale di Geofisica e Vulcanologia develops station-level detection probabilities and combines them across a seismic network to compute magnitude-of-completeness fields. They apply this approach to two catalogs from Central Italy constructed from the same seismic network: one routine, and one machine learning-based. They found that at the station level, the machine learning picker increases detection sensitivity and decreases the magnitude of completeness (which means that the station has detected all earthquakes of even smaller magnitudes, a tough task). However, the authors also found that the machine learning catalog showed greater variability in station-level performance than the routine catalog.

https://pubs.geoscienceworld.org/ssa/srl/article/doi/10.1785/0220250453/728683/Variability-in-Performance-of-a-Machine-Learning?utm_source=facebook&utm_medium=social&utm_campaign=papers

⏳️ Time is running out ... to register for our 23 June sessions all about SSA programs!Join us to learn how you can ap...
06/18/2026

⏳️ Time is running out ... to register for our 23 June sessions all about SSA programs!

Join us to learn how you can apply for Community and Global Travel Grants, opening next month: https://buff.ly/GWmleIS

Full Moment Tensor Inversions of Microseismic Events Revealing Fault Activation of the 17 August 2015 Earthquake in the ...
06/18/2026

Full Moment Tensor Inversions of Microseismic Events Revealing Fault Activation of the 17 August 2015 Earthquake in the Northern Montney Formation, British Columbia, Canada

Full moment tensor source mechanisms (imagine beachball diagrams) of microseismic and induced earthquakes can help scientists investigate how faults fail during hydraulic fracturing, wastewater injection and other anthropogenic activities. Quantifying uncertainty is especially important, and can be difficult when station coverage is uneven or limited.

In a new study, a team from the University of Toronto and the Geological Survey of Canada uses data collected by an array of 198 geophones on the surface of hydraulic fracturing operations of the Montney formation in British Columbia. The data span August and September of 2015. The team inverted high-frequency P-phase amplitude ratios using the open-source package MTUQ.

This analysis yielded moment tensors and uncertainties resolved for 567 events. Foreshocks pointed to tensile opening, linked to fluid injection processes. Aftershocks indicated fluid migration and aseismic slip through newly formed pathways.

https://pubs.geoscienceworld.org/ssa/bssa/article/doi/10.1785/0120250267/728902/Full-Moment-Tensor-Inversions-of-Microseismic?utm_source=facebook&utm_medium=social&utm_campaign=papers

The Potential Impact of Three‐Dimensional Distributed Slip Models Derived from Real‐Time GNSS Data on the Performance of...
06/17/2026

The Potential Impact of Three‐Dimensional Distributed Slip Models Derived from Real‐Time GNSS Data on the Performance of the ShakeAlert Earthquake Early Warning System for Slab Interface Earthquakes

The U.S. West Coast’s ShakeAlert earthquake early warning system warns users of incoming strong ground motion. The alert’s recipients may then have precious seconds to take protective actions.

ShakeAlert uses three algorithms to characterize the earthquake source. The first estimates location and magnitude quickly, but may underestimate magnitudes for very large events (greater than magnitude 7.0). The second estimates location, orientation, length and magnitude, contributing to earthquakes greater than magnitude 5.5. The third infers magnitude from peak ground displacement using GNSS data, and is especially useful for earthquakes with magnitudes greater than 7.0.

In a new paper, a team from the U.S. Geological Survey (USGS) and the University of Washington evaluates the potential contribution of another algorithm, BEFORES, to improve ShakeAlert performance through simulated real-time implementation of Bayesian evidence‐based fault orientation and real‐time earthquake slip (BEFORES). To conduct this evaluation, they use data for eight earthquakes with magnitudes greater than or equal to 7.6.

The team found that BEFORES can produce well‐constrained and accurate magnitude estimates as soon as or sooner than other algorithms — providing precious warning time. However, at the current shaking threshold, BEFORES would tend to alert large geographic regions that did not feel strong shaking, an affect potentially mitigated with a higher alerting threshold.

https://pubs.geoscienceworld.org/ssa/bssa/article/doi/10.1785/0120250235/730492/The-Potential-Impact-of-Three-Dimensional?utm_source=facebook&utm_medium=social&utm_campaign=papers

Machine Learning–Based Automatic Microseismic Event Detection During the 17 August 2015 Mw 4.6 Induced Earthquake Sequen...
06/16/2026

Machine Learning–Based Automatic Microseismic Event Detection During the 17 August 2015 Mw 4.6 Induced Earthquake Sequence in Northern Montney, British Columbia, Canada

In hydraulic fracturing operations, monitoring microseismicity is critical for understanding fracture growth and reservoir behavior, while also illuminating induced earthquake processes and associated seismic hazards. Successful monitoring efforts require correctly detecting seismic events and picking P- and S- waves arrivals.

In a new study, a team from the University of Toronto and the Geological Survey of Canada conducts a controlled benchmark of state-of-the-art deep learning models for microseismic event detection. They use a geophone dataset recorded in 2015 during hydraulic fracturing operations in the northern Montney play of British Columbia, Canada. The team presents a fully open-source machine learning-based workflow that successfully detects and locates microseismic events based on comparison with an industry catalog.

https://pubs.geoscienceworld.org/ssa/bssa/article/doi/10.1785/0120250263/730493/Machine-Learning-Based-Automatic-Microseismic?utm_source=facebook&utm_medium=social&utm_campaign=papers

ONE WEEK FROM TODAY!Join us on 23 June to learn all about SSA grants! We have two 30-minute sessions where you can get a...
06/16/2026

ONE WEEK FROM TODAY!
Join us on 23 June to learn all about SSA grants! We have two 30-minute sessions where you can get all your questions answered.
Register now: https://buff.ly/GWmleIS

In this month's SSA At Work, Irene Liou discusses the challenges of making physics-based more accessible: https://buff...
06/15/2026

In this month's SSA At Work, Irene Liou discusses the challenges of making physics-based more accessible: https://buff.ly/JrIZmjO

📢CALL FOR PAPERS📢 is soliciting manuscripts for a Special Issue on Complex Multi-Fault EarthquakesDeadline for Submissi...
06/15/2026

📢CALL FOR PAPERS📢 is soliciting manuscripts for a Special Issue on Complex Multi-Fault Earthquakes

Deadline for Submission: 1 July 2026

Recognizing the approaching 10th anniversary of the Kaikōura, New Zealand earthquake, BSSA invites contributions to a special issue on understanding, modeling and forecasting complex multi-fault earthquakes.

The Mw 7.8 Kaikōura earthquake on 15 November 2016 was an unusually complex multi-fault earthquake, involving slip on at least 20 faults with a wide range of fault geometries, kinematics and depths. Several subsequent multi-fault ruptures, notably the 6 February 2023 Türkiye-Syria, 1 January 2024 Noto, Japan, and 5 December 2024 Mendocino, California earthquakes, have since illustrated that these types of ruptures occur in diverse tectonic settings, constitute a significant hazard locally and even regionally, and hence are of global importance. Complex multi-fault earthquakes pose numerous scientific challenges including their recognition in the paleoseismic record, interpretation and modeling of slip transfer processes, understanding the source dynamics that lead to such cascading earthquake ruptures, estimating ground motions, and developing seismic hazard models for spatially extensive fault networks.

BSSA invites special issue contributions that address the diversity of seismotectonic problems posed by complex multi-fault earthquakes, including field-based, computational, forecasting and hazard studies. Multidisciplinary contributions and those addressing secondary hazard processes such as landslides and tsunamis are particularly welcome.

Guest editors include:

Ryo Ando - The University of Tokyo / UTokyo
Zoë Mildon - University of Plymouth
Kevin Milner - U.S. Geological Survey (USGS)
Vasiliki Mouslopoulou - National Observatory of Athens
Andy Nicol - University of Canterbury

https://www.seismosoc.org/publications/calls-papers/bssa-call-for-papers-11/

🌟 OPEN ACCESS 🌟 Surface Rupture and Slip Distribution of the 2025 Mw 7.7 Mandalay Earthquake and Updated Length Scaling ...
06/15/2026

🌟 OPEN ACCESS 🌟 Surface Rupture and Slip Distribution of the 2025 Mw 7.7 Mandalay Earthquake and Updated Length Scaling of Supershear Earthquakes

In March of 2025, a magnitude 7.7 earthquake struck Mandalay, Myanmar (Burma). The earthquake ruptured the central Sagaing Fault. At a length of 475 kilometers, this is the longest continental strike-slip rupture on record. Magnitude-scaling relations would suggest a rupture length of between 100 to 300 kilometers. Why the discrepancy?

In a new paper, a team from the U.S. Geological Survey (USGS), 國立臺灣大學 National Taiwan University and 國立中正大學（National Chung Cheng describes the character, length, and slip distribution of the surface rupture based on satellite data. The team found that 87% of the rupture tore a single strand of the fault, which they attribute to supershear speed, simple fault geometry, a narrow deformation zone, and moderate surface slip. The team also proposes a different length-magnitude scaling relation for supershear earthquakes based on their observation that these events tend to have longer ruptures than their subshear counterparts.

https://pubs.geoscienceworld.org/ssa/srl/article/97/3/1697/728831/Surface-Rupture-and-Slip-Distribution-of-the-2025?utm_source=facebook&utm_medium=social&utm_campaign=papers

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