报告地点：腾讯会议(会议ID：411 4788 6096）
报告时间：2020-11-13 从 10:00 到 11:30
报告人：许效华
报告人简介：
许效华，2012年于中国科学技术大学获得地球物理学学士学位，2017年于美国Scripps海洋研究所（加州大学圣地亚哥）获得地球科学博士学位，此后继续在所内任职博士后；主要从事InSAR技术开发与地球物理学应用的研究，是开源InSAR处理软件GMTSAR的主要研发者之一，研究兴趣包含震源物理，地壳形变，应变应力累积过程，InSAR/GNSS相结合等。
报告题目：What can we learn from the surface fractures nearby the Ridgecrest earthquakes?
报告内容简介
Contemporary earthquake hazard models hinge on an understanding of how strain is distributed in the crust and the ability to precisely detected mm-scale deformation over broad regions of active faulting. Satellite radar observations revealed hundreds of previously unmapped linear strain concentrations (or fractures) surrounding the 2019 Ridgecrest earthquake sequence. We documented and analyzed displacements and widths of 169 of these fractures. While most fractures are displaced in the direction of the prevailing tectonic stress (prograde), a large number of them are displaced in the opposite (retrograde) direction. We constructed fault slip model and computed static Coulomb stress change for a suite of receiver fault orientations consistent with those exhibiting surface fractures. Comparing static stress change models to the phase gradient maps, we were able to determine that these surface fractures can largely be explained with static stress change from the earthquake sequence, with most antithetic motions are associated with compliant fault deformation, where most prograding ones being shallow frictional slip. We further explore a conceptual model that can explain these observations. One important implication from the model is that much of the “off-fault” strain in the Mojave shear zone is due to permanent inelastic deformation on many small faults. This is in support of the hypothesis that compensation of shallow slip deficit occurs on distributed shallow structures.