Japan Geoscience Union Meeting 2022

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[E] Poster

S (Solid Earth Sciences ) » S-SS Seismology

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

Tue. May 31, 2022 9:00 AM - 11:00 AM Online Poster Zoom Room (17) (Ch.17)

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)


9:00 AM - 11:00 AM

[SSS04-P02] Optimized procedure on the main rupture directivity: application to the 2016-2018 Central Italy seismic sequence

*Giovanna Calderoni1, Rita Di Giovambattista1, Guido Ventura1 (1.Istituto Nazionale di Geofisica e Vulcanologia)

Keywords:directivity, fluids, immediate aftershocks

We present an optimized procedure to estimate the main direction of rupture propagation during a seismic sequence. We apply this procedure to the strongest earthquakes (Mw greater than 4.4) of the 2016-2018 Central Italy seismic sequence and compare our results with other studies. We find a heterogeneity of rupture directivity along the complex activated fault system. We observe that the preferred trend of the rupture propagation is in large part controlled by pre-existing structural discontinuities, i.e., the NW-SE faults and NE-SW lateral ramps. We suggest that pre-existing structural discontinuities may control the directivity in the way that such discontinuities represent weakness zone, i.e., zones affected by a bi-material fault interface. We also discuss the possible role of fluids as a cause of bi-material controlling the earthquake main rupture direction. Furthermore, we investigate possible control of main rupture directivity on the location of immediate aftershocks. We find that immediate seismicity mainly appears to be correlated with main rupture directivity along the pre-existing structural discontinuities.