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为分析2008年5月12日四川汶川M_s 8.0级地震对周边断层地震活动的影响,本文首先基于Burgers体黏滞松弛模型计算汶川M_s 8.0级地震引起的库仑应力动态演化,分析认为2008年汶川M_s 8.0级地震在周边断层上引起的库仑应力显著增加的主要有四个断层段,分别为鲜水河断裂道孚康定段、东昆仑断裂东段玛曲段、青川断裂和龙门山断裂南段.而且震后4年内黏滞松弛引起的库仑应力变化量可能与同震变化相当,相当于再发生一次汶川地震所造成的影响,因此震后效应在分析强震影响时不应忽略.本文基于强震引起的库仑应力变化动态演化,结合背景地震发生率、由Dieterich(1994)模型给出地震发生概率,结合相关构造地质、历史地震、余震活动等方面资料的综合分析认为,上述4个断裂段地震危险性由高到低依次为鲜水河断裂道孚—康定段、龙门山断裂南段、东昆仑断裂东段玛曲段和青川断裂.
In order to analyze the influence of M_s 8.0 Wenchuan earthquake on the seismic activity of the surrounding faults on May 12, 2008, this paper first calculates the dynamic evolution of Coulomb stress caused by the Wenchuan M_s 8.0 earthquake based on the Burgers bulk relaxation model. It is considered that the Wenchuan M_s The Ms8.0 earthquake caused a significant increase in Coulomb stress on the surrounding faults. There are mainly four fault segments, namely, the Fukang segment of the Xianshuihe fault, the Maqu segment of the East Kunlun fault, the Qingchuan fault and the southern part of the Longmenshan fault. And the change of Coulomb stress caused by the viscous relaxation within 4 years after the earthquake may be equivalent to the coseismic change, equivalent to the impact caused by the recurrence of a Wenchuan earthquake, so the post-earthquake effect should not be neglected when analyzing the impact of strong earthquakes. According to the dynamic analysis of Coulomb stress changes caused by the earthquake, combining with the occurrence rate of background earthquakes, the probability of earthquakes is given by Dieterich (1994) model. According to the comprehensive analysis of related tectonic geology, historical seismics and aftershock activity, Seismic hazard descending order: Xianshuihe fault, Kangding segment, southern segment of Longmenshan fault, Maqu of eastern Kunlun fault And Qingchuan fault.