Evaluation of the seismic moment of the April 20,2013 Lushan earthquake  

作　　者：Xiaogang Hu Ying Jiang 

机构地区：[1]Laboratory of Geodesy and Earth’s Dynamics,Institute of Geodesy and Geophysics,Chinese Academy of Sciences

出　　处：《Earthquake Science》2013年第3期169-177,共9页地震学报（英文版）

基　　金：supported by National Natural Science Foundation of China(Nos.41174022 and 41021003)

摘　　要：The April 20, 2013 Lushan earthquake which occurred in Sichuan, China had only moderate thrust. However, the computed seismic moments （M0） for the Lushan earthquake calculated by several institutions differ significantly from 0.4 × 1019 to 1.69 ×019 Nm, up to four times difference. We evaluate ten computed Mos by using normal mode observations from superconducting gravimeters in China's Mainland. We compute synthetic normal modes on the basis of moment tensor solutions and fit them to the observed normal modes. Comparison of our results indicates that Mo is the main cause for some large differences between observations and synthetics. We sug- gest that a moment magnitude of Mw6.6, corresponding to a Mo of 0.97-1.08 × 1019 Nm, characterizes the size and strength of the seismic source of the Lushan earthquake.The April 20, 2013 Lushan earthquake which occurred in Sichuan, China had only moderate thrust. However, the computed seismic moments （M0） for the Lushan earthquake calculated by several institutions differ significantly from 0.4 × 1019 to 1.69 ×019 Nm, up to four times difference. We evaluate ten computed Mos by using normal mode observations from superconducting gravimeters in China's Mainland. We compute synthetic normal modes on the basis of moment tensor solutions and fit them to the observed normal modes. Comparison of our results indicates that Mo is the main cause for some large differences between observations and synthetics. We sug- gest that a moment magnitude of Mw6.6, corresponding to a Mo of 0.97-1.08 × 1019 Nm, characterizes the size and strength of the seismic source of the Lushan earthquake.

关 键 词：Free oscillations Moment tensorsolution Seismic moment 

分 类 号：P315[天文地球—地震学]