Source parameters inversion of the 2013 Lushan earthquake by combining teleseismic waveforms and local seismograms

• Published in: Science China. Earth sciences 2013-07, Vol.56 (7), p.1177-1186
• Main Authors: Xie, ZuJun, Jin, BiKai, Zheng, Yong, Ge, Can, Xiong, Xiong, Xiong, Cheng, Hsu, HouTze
• Format: Article
• Language: English
• Subjects: Broadband; China; Earth and Environmental Science; Earth Sciences; Earthquakes; Geophysics; Inversions; Mathematical models; Plate tectonics; Research Paper; Seismic activity; Seismic phenomena; Seismograms; Seismology; Strikes; Waveforms; 参数反演; 地震源; 宽带波形; 庐山; 远震; 速度模型; 震源机制; 震源深度
• ISSN: 1674-7313; 1869-1897
• DOI: 10.1007/s11430-013-4640-3

On April 20, 2013, a magnitude Ms7.0 earthquake occurred in Lushan, Sichuan Province, China, and caused heavy casualties and economic losses. Based on the local broadband waveforms in Sichuan and adjacent provinces regional networks and teleseismic broadband records from IRIS stations, the focal mechanism and the focal depth are determined by the CAP （Cut And Paste） and its upgraded methods, CAPtele and CAPjoint, respectively. The results show that the focal mechanisms and depth from different methods are steady, and the best double couple solution derived from the joint inversion is 210°, 44°, and 91°for strike, dip, and rake angles respectively for one nodal plane and 29°, 46°, and 89° for another with 16 km focal depth and Mw6.66 moment magnitude. In order to verify the reliability of the results, a number of tests are performed based on local seismograms with different velocity models. They indicate that there is about 10 degree＇s fluctuation in focal mechanisms and about 2 km variation in focal depth with a complex velocity structure. Furthermore, inverted by re-sampling the teleseismic waveforms on the basis of epicentral distance, the solutions are consistent with each other, which manifests that the teleseismic records are effective for constraining source parameters of the Lushan earthquake.