Interpreting the Coseismic Uplift and Subsidence of the Longmen Shan Foreland Basin System during the Wenchuan Earthquake by a Elastic Flexural Model

作     者：YAN Zhaokun LI Yong SHAO Chongjian ZHOU Rongjun YAN Liang ZHAO Guohua YAN Binglei 

作者机构：State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (CDUT) Chengdu 610059 China Sichuan Earthquake Administration Chengdu 610041 China 

出 版 物：《Acta Geologica Sinica(English Edition)》 (地质学报（英文版）)

年 卷 期：2016年第90卷第2期

页      面：555-566页

核心收录：

学科分类：070801[理学-固体地球物理学] 0709[理学-地质学] 0819[工学-矿业工程] 07[理学] 0708[理学-地球物理学] 0818[工学-地质资源与地质工程] 0816[工学-测绘科学与技术] 

基　　金：funded by the National Natural Science Foundation of China(Grant No.41502116,40841010,40972083,41172162,41372114,and 41340005) the National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Grant No.SK–0801) 

主　　题：flexural model Longmen Shan Wenchuan Earthquake coseismic uplift and subsidence foreland basin system 

摘      要：The coseismic surface uplift of the Longmen Shan（LMS） created an instantaneous topographic load over the western margin of the Sichuan Basin, where surface subsidence, decreasing eastward, has been measured using several methods, such as GPS, SAR and levelling. Using an elastic flexural model, we aim to interpret the coseismic surface uplift and subsidence, and constrain the effective lithospheric elastic thickness（Te） of the Sichuan Basin. Using different effective elastic thickness values for the Sichuan Basin, a series of subsidence curves were computed by the elastic flexure model equation for a broken elastic plate. The curves, produced by models using an effective elastic thickness of 30–40 km, provided the best fit to the general pattern of observed coseismic subsidence of the Sichuan Basin. However, the calculated subsidence（-40–70 cm） at the front of the LMS is evidently lower than the observed values（-100 cm）, suggesting that the effective elastic thickness therein should be lower. These results indicate that the lithospheric strength may decrease westward from the Sichuan Basin to the LMS.