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Evaluation of the seismic moment of the April 20, 2013 Lushan earthquake |
Xiaogang Hu, Ying Jiang |
Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China |
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Abstract 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 1.69×1019 Nm, up to four times difference. We evaluate ten computed M0s by using normal mode observations from superconducting gravimeters in Mainland China. 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 M0 is the main cause for some large differences between observations and synthetics. We suggest that a moment magnitude of Mw6.6, corresponding to a M0 of 0.97–1.08×1019 Nm, characterizes the size and strength of the seismic source of the Lushan earthquake.
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Received: 25 June 2013
Published: 20 November 2013
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Fund:National Natural Science Foundation of China (Nos. 41174022 and 41021003) |
Corresponding Authors:
Xiaogang Hu
E-mail: hxg432@whigg.ac.cn
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