地震研究

以2014年四川康定MS6.3和MS5.8地震为研究对象,计算了2次主震在近场和周围断层造成的库仑破裂应力变化,研究主震与余震的触发关系,以及2次主震对周围断层施加的应力负荷作用。结果表明:2次主震的共同作用控制了后续地震活动的演化趋势,其中康定MS6.3地震产生的库仑破裂应力变化对后续余震事件的触发占主导作用。鲜水河断裂带南段和安宁河断裂带受到了一定的应力加载作用,未来地震活动的趋势可能会加强。

In this study,the problem of earthquake triggering is discussed by using the MS6.3 earthquake on Nov.22,2014 and the MS5.8 earthquake on Nov.25,2014 in Kangding,Sichuan Province.Firstly,based on the regional tectonic stress field in this area,we calculated the spatial distributions of static stress changes caused by the Kangding MS6.3 and MS5.8 earthquakes on the optimal fault planes,and studied the stress triggering effect of the main shock to the aftershocks.Furthermore,we analyzed the stress loading and unloading effects of the two main-shocks on the surrounding faults by calculating the Coulomb rupture stress changes on the surrounding faults.The results show that the joint action of the two main earthquakes controls the evolution trend of the subsequent seismicity.Moreover,the Coulomb failure stress change produced by the Kangding MS6.3 earthquake has a good correlation with the aftershocks,and the triggering effect on the subsequent events is dominant.In addition,the southern segment of the Xianshuihe fault and the Anninghe fault are subjected to certain stress loading by two earthquakes,and the seismic activity may be strengthened in the future.

引言
1 研究方法
2 构造背景
3 主震震源模型
4 计算结果分析
5 结论

图1 研究区构造背景<br/>Fig.1 Tectonic background of the study area

图1 研究区构造背景
Fig.1 Tectonic background of the study area

表1 区域构造应力场主要参数<br/>Tab.1 Main parameters of regional tectonic stress field

表1 区域构造应力场主要参数
Tab.1 Main parameters of regional tectonic stress field

表2 2014年康定MS6.3和MS5.8地震的震源模型主要参数<br/>Tab.2 Main parameters of source models of the Kangding MS6.3 and MS5.8 earthquakes in 2014

表2 2014年康定MS6.3和MS5.8地震的震源模型主要参数
Tab.2 Main parameters of source models of the Kangding MS6.3 and MS5.8 earthquakes in 2014

图2 2014年康定MS6.3(a)和MS5.8(b)地震震源模型的滑动分布<br/>Fig.2 Slip distribution of source models for the Kangding MS6.3(a)and MS5.8(b) earthquakes in 2014

图2 2014年康定MS6.3(a)和MS5.8(b)地震震源模型的滑动分布
Fig.2 Slip distribution of source models for the Kangding MS6.3(a)and MS5.8(b) earthquakes in 2014

图3 2014年康定MS6.3(a)和MS5.8(b)地震产生的库仑应力变化及余震事件的空间分布<br/>Fig.3 Coulomb stress changes induced by the Kangding MS6.3(a)and MS5.8(b) earthquakes and the spatial distribution of aftershocks

图3 2014年康定MS6.3(a)和MS5.8(b)地震产生的库仑应力变化及余震事件的空间分布
Fig.3 Coulomb stress changes induced by the Kangding MS6.3(a)and MS5.8(b) earthquakes and the spatial distribution of aftershocks

图4 2014年康定2次主震产生的库仑应力变化与后续余震活动的空间分布受有效摩擦系数μ'影响<br/>Fig.4 Coulomb stress changes induced by two Kangding earthquakes in 2014 and the spatial distribution of their aftershocks influenced by different effective friction coefficient μ'

图4 2014年康定2次主震产生的库仑应力变化与后续余震活动的空间分布受有效摩擦系数μ'影响
Fig.4 Coulomb stress changes induced by two Kangding earthquakes in 2014 and the spatial distribution of their aftershocks influenced by different effective friction coefficient μ'

表3 研究区主要断裂带的参数<br/>Tab.3 Parameters of faults in the study area

表3 研究区主要断裂带的参数
Tab.3 Parameters of faults in the study area

图5 2014年康定2次主震在附近断裂上引起的库仑破裂应力分布<br/>Fig.5 Distributions of Coulomb stress changes on the nearby faults induced by two Kangding earthquakes in 2014

图5 2014年康定2次主震在附近断裂上引起的库仑破裂应力分布
Fig.5 Distributions of Coulomb stress changes on the nearby faults induced by two Kangding earthquakes in 2014

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备注

引言

1 研究方法

2 构造背景

3 主震震源模型

4 计算结果分析

5 结论

期刊信息