Japan Geoscience Union Meeting 2022

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[E] Oral

S (Solid Earth Sciences ) » S-SS Seismology

[S-SS04] Seismic Spectra for Source, Subsurface Structure, and Strong-motion Studies

Mon. May 23, 2022 9:00 AM - 10:30 AM 103 (International Conference Hall, Makuhari Messe)

convener:Takahiko Uchide(Research Institute of Earthquake and Volcano Geology, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), convener:Rachel E Abercrombie(Boston University), Kuo-Fong Ma(Institute of Geophysics, National Central University, Taiwan, ROC), convener:Kazuhiro Somei(Geo-Research Institute), Chairperson:Takahiko Uchide(Research Institute of Earthquake and Volcano Geology, Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Rachel E Abercrombie(Boston University), Kuo-Fong Ma(Institute of Geophysics, National Central University, Taiwan, ROC), Kazuhiro Somei(Geo-Research Institute)


10:00 AM - 10:15 AM

[SSS04-05] Characterization of Earthquake Sources in Diverse Tectonic Settings

*Rachel E Abercrombie1 (1.Boston University, Boston, USA)

Keywords:earthquake, stress drop, source complexity

Detailed analysis of well-recorded earthquake sequences, tectonic and induced, has the potential to reveal the relative influence of multiple processes on earthquake nucleation and rupture propagation. High precision relocations enable mapping of seismicity migration rates, indicative of fluid or aseismic forcing. Combined with focal mechanisms, the relocations reveal the active structures and their relative stress states. Source analysis provides information about the finite rupture extents, and rupture directions, which are needed to constrain earthquake interactions and triggering. Earthquake stress drop, rupture propagation direction, and even source complexity may depend on local conditions resolvable by seismicity characteristics. However, all these parameters are hard to resolve unambiguously because of the limited frequency range of most recordings, and the need to remove the effects of attenuation and other path effects. My recent work on tectonic and induced earthquakes in western and central United States and beyond, with many coauthors, has provided insights into resolution and uncertainties. It has also revealed spatial and temporal variations of stress drop in both swarms and repeating earthquake sequences that may help us understand the factors governing earthquake rupture. I will summarize some of these recent results, and discuss their implications.