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Generous to a fault: How including both seismic and geodetic datasets improves earthquake slip characterization

Date(s): April 27, 2023, 2-3pm Eastern
Location: Virtual

Speaker: Dr. Dara Goldberg (USGS)

Following an earthquake of interest, deciphering the spatiotemporal details of the rupture help to inform shaking predictions, loss estimates, and damage assessments. Shaking is related to a location’s distance from slip asperities; however, rupture directivity can result in variable shaking and damage at different azimuths, despite similar distances from the rupture. The U.S. Geological Survey National Earthquake Information Center (NEIC) produces a slip model (known as a finite fault model, FFM) within hours of a significant earthquake. In the past, these models have been produced with broadband teleseismic data, for which it is generally feasible to model earthquakes of magnitude 7 and larger globally. Peer-reviewed research products have demonstrated that incorporating regional-distance seismic and geodetic observations, where available, can improve model quality and the accuracy of downstream impact products. In addition, these high-quality research products contribute to general knowledge of the earthquake rupture process, including magnitude-dependent qualities of rupture (i.e., earthquake scaling laws) and specific attributes of well-instrumented fault systems (e.g., rupture propagation speeds). In this talk, I will demonstrate recent updates to NEIC operations that move us toward producing these joint regional/teleseismic seismo-geodetic FFMs in a response time frame (hours). Including regional seismic and geodetic datasets enhances our ability to model smaller magnitude earthquakes than NEIC previously considered for rapid slip characterization and improves model resolution for earthquakes of any size. I will highlight recent results from the 2023 Kahramanmaraş, Türkiye, Earthquake Sequence. The integration of local seismic and geodetic observations, available in the days following the earthquakes, helped to clarify both the lateral- and depth-extent of slip, and confirms the benefit of local observations in NEIC response models.