On the occurrence of orthogonal faulting

徐世庆 博士

南方科技大学

2020.12.11（星期五）10:00，理科二号楼2821

报告摘要：

An increased number of observations have reported orthogonal faulting during some large crustal earthquakes. Traditionally, orthogonal faulting was thought to be incompatible with Anderson’s theory of faulting or Mohr-Coulomb failure criterion, if the faulting process is governed by brittle failure associated with a friction coefficient of about 0.6. Various ideas have been proposed to reconcile the incompatibility, by invoking fault/block rotation, ductile failure, and high pore fluid pressure. Here, I propose an alternative mechanism in that seismic loading can generate nearly orthogonal faulting, without requiring ductile failure or anomalously high pore fluid pressure. The key ingredient of this mechanism relies on that the loading stress during earthquakes is different from the ambient background stress, such that an “unusual” pattern of orthogonal faulting can still be generated. I test this idea by running numerical simulations and could confirm its viability. I also find that rupture deceleration/termination and pre-existing plane of weakness can further facilitate the generation of orthogonal faulting. Finally, I cite many earthquake examples, reported in nature and in the laboratory, to support the above mechanism. The results suggest that orthogonal faulting is not unusual at all. Further more, there is a need to revise the basic theories of earthquakes and faulting.

报告人简介：

 徐世庆，2007年本科毕业于北京大学，2013年于美国南加州大学获地质学博士学位，2013年至2019年在日本防灾科学技术研究所从事研究工作。2019年9月加入南方科技大学地球与空间科学系，任助理教授。以第一作者或者共同作者在EPSL，JGR，Nature等期刊上发表论文19篇。多次为国际知名期刊和美国自然科学基金委担任同行评审。2018年获评日本地震学会青年科学家奖。2019及2020年获评AGU下属期刊JGR 优秀审稿人称号。

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