1833年嵩明8.0级地震对周围断层的影响

The influence of 1833 Songming M 8.0 earthquake on surrounding faults

应用粘弹性计算程序,计算1833年嵩明8.0级大地震产生的同震和震后应力场变化,并计算对附近的小江断裂带、安宁河断裂带、则木河断裂带及云南境内红河断裂带造成的同震和震后库仑应力变化。结果表明,嵩明8.0级大地震对滇中南地区应力分布产生较大影响,对周围断层的影响甚至持续数百年的时间。嵩明8.0级地震使震中附近的小江断裂中段、安宁河断裂南段和红河断裂带中段库仑应力减小,降低发震危险;而小江断裂带南北段、安宁河断裂北段、则木河断裂带和红河断裂带南北两段库仑应力增加,地震危险性增强。红河断裂带中段在数百年时间尺度内始终处于嵩明8.0级地震库仑应力的减小区域,该研究结果有助于解释此断裂段的地震平静现象。

Based on the viscoelastic model,we calculated the coseismic and post seismic impact on the surrounding areas caused by the1833Songming M8.0earthquake.Furthermore,we analyze the coseismic and post seismic Coulomb stress changes on the Xiaojiang,Anninghe,Zemuhe and the Red River faults.The results show that this large earthquake had a significant impact on the whole Yunnan area and the main faults,which maybe last several hundred of years.The Coulomb stresses on the central segment of Xiaojiang fault,the southern segment of Anninghe and the central segment of Red River fault decrease,that is,the correspond faults are brought farther away from failure.The activities on the southern and northern segments of Xiaojiang fault,the northern segment of Anninghe fault,the whole Zemuhe fault,the northern and southern segments of Red River fault are loaded.Particularly for the central segment of the Red River fault zone,the Coulomb stress change trend helps to explain the observed earthquake‘pece period’,and this stable status may remain several hundred years.