Post-Seismic Deformation Processes:Afterslip and Vicoelastic Relaxation Following the 2015 Nepal Mw7.8 Earthquake

被引：0
|
作者：
Li Y. [1 ]
Zhang Y. [1 ]
Wang S. [2 ]
Liu T. [3 ]
机构：
[1] School of Geology Engineering and Geomatics, Chang'an University, Xi'an
[2] School of Geodesy and Geomatics, Wuhan University, Wuhan
[3] Key Laboratory of Earthquake Prediction, Institute of Earthquake Science, China Earthquake Administration, Beijing
来源：
Wuhan Daxue Xuebao (Xinxi Kexue Ban)/Geomatics and Information Science of Wuhan University | 2020年 / 45卷 / 10期
基金：
中国国家自然科学基金;
关键词：
2015 Nepal Mw7.8 earthquake; Fault afterslip; GPS data; Spherical dislocation theory; Viscoelastic relaxtion;
D O I：
10.13203/j.whugis20180349
中图分类号：
学科分类号：
摘要：
The post-earthquake deformation mechanism of the 2015 Nepal Mw7.8 earthquake is studied by using the relatively perfect theory of spherical displacement and GPS data of one year after Nepal earthquake. Two different models of post-earthquake deformation mechanism are explored: ① Single post-earthquake afterslip model (model 1); ② Combined model of post-earthquake afterslip and viscous relaxation (model 2). The results of model 1 show that the post-earthquake afterslip mainly occurs at the depth of 20-35 km and is located in the downdip area of co-seismic rupture; the main component of afterslip is thrust, accompanied by dextral strike-slip components, of which the largest component is 20 cm and 11 cm, respectively; the moment released by the post-earthquake afterslip is 1.23×1020 Nm,equivalent to Mw7.33 earthquake. The residual slip distribution obtained by model 2 is consistent with model 1, but the cumulative slip is slightly smaller, and the released seismic moment is 1.1×1020 Nm, equivalent to Mw7.32 earthquake. Furthermore,the results of model 2 show that the optimum values of lithospheric elastic layer thickness and mantle viscous coefficient in Nepal seismic source area are 40 km and 2×1019 Pa•s, respectively. To sum up, the post-earthquake afterslip effect plays a dominant role and the viscous relaxation effect plays a secondary role in Nepal within one year after the earthquake. © 2020, Editorial Board of Geomatics and Information Science of Wuhan University. All right reserved.
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页码：1578 / 1587
页数：9
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