日本地球惑星科学連合2022年大会

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[E] ポスター発表

セッション記号 S (固体地球科学) » S-SS 地震学

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

2022年5月31日(火) 09:00 〜 11:00 オンラインポスターZoom会場 (17) (Ch.17)

コンビーナ:内出 崇彦(産業技術総合研究所 地質調査総合センター 活断層・火山研究部門)、コンビーナ:Abercrombie Rachel E(Boston University)、Ma Kuo-Fong(Institute of Geophysics, National Central University, Taiwan, ROC)、コンビーナ:染井 一寛(一般財団法人地域地盤環境研究所)、座長:内出 崇彦(産業技術総合研究所 地質調査総合センター 活断層・火山研究部門)、Rachel E Abercrombie(Boston University)、Ma Kuo-Fong(Institute of Geophysics, National Central University, Taiwan, ROC)、染井 一寛(一般財団法人地域地盤環境研究所)


09:00 〜 11:00

[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)

キーワード：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.