摘要
首先利用ALOS PALSAR数据,通过D-InSAR技术获取2007-06-03云南宁洱M_S6.4地震的同震形变场,然后基于Okada弹性半空间位错模型反演该地震的断层几何以及精细滑动分布,最后计算宁洱地震后周边断层的静态库仑应力变化。结果表明,形变主要集中在西盘,最大视线向形变量为51.6 cm;反演得到的震源位置为23.05°N、101.02°E,深度3 km,断层走向145°,倾向49.5°,平均滑动角153°,发震断层为NNW向普洱断裂,断层活动以右旋走滑为主,兼具逆冲分量;断层面最大滑动量为1.2 m,反演得到的震级为M_W6.19。基于库仑应力场发现,磨黑断裂处于库仑应力增加区域,而2014年景谷地震位于负值区域。结合实地考察资料和反演结果表明,宁洱地震为浅源地震,但断层并未出露地表。
A M_S6.4 earthquake struck Ning'er county of Pu'er city in Yunnan, China on June 3, 2007. In this paper, we extract the coseismic deformation field by two-pass differential interferometric SAR(D-InSAR) technology from ALOS PALSAR data. Based on the Okada half-space elastic model, the fault geometry of such earthquake and the corresponding fault slip distribution parameters are then calculated, as well as the changes of Coulomb stress around the fault after the earthquake. The results show that the maximum deformation occurred in the west wall of the fault, with a 51.6 cm deformation in the line-of-sight direction. And the epicenter of the inversion is located in 23.05°N, 101.02°E, of which the focal depth is 3 km, the strike is 145°, the dip is 49.5° and the rake is 153°. We infer that the NNW direction of Pu'er fault is a causative fault, where the main motion characteristics are right-lateral strike-slip, with thrusting component, of which the maximum value of slippage is 1.2 m, and the inversion magnitude is M_W6.19. According to the Coulomb stress field, we find that the Mohei fault is located in the area of increasing Coulomb stress, while Jinggu earthquake is located in the area of negative Coulomb stress. In addition, considering both the field investigation data and experimental results, as a shallow earthquake, there is no rupture zone on the surface of Ning'er earthquake.
引文
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