地震研究

根据芦山7.0级地震震源破裂过程的最新研究结果,采用3个震源模型计算了地震产生的库仑破裂应力变化,研究了库仑破裂应力变化的空间分布与余震活动分布的关系,探讨芦山地震的发生对滇东地区影响。结果表明,90%以上芦山地震的后续地震活动分布于正的库仑破裂应力区域,余震活动受到了主震的应力触发作用。滇东地区一直处于应力闭锁状态,芦山7.0级地震的发生,可能对滇东的小江断裂带及其以西地区有一定的应力触发作用。

The Lushan M_S7.0 earthquake occurred on Apr.20,2013 in Lushan Country,Ya'an City,Sichuan Province. According to the newest research results of source rupture process for Lushan M_S7.0 earthquake,we used three source models to calculate the coulomb failure stress changes induced by the Lushan M_S7.0 earthquake,and analyze the relationship between the spatial distribution of coulomb failure stress changes and the aftershock activity distribution. Moreover,we discussed the influence of Lushan M_S7.0 earthquake on the Eastern Yunnan. The results show that the more than 90% of aftershock activities distributed in the areas with the positive coulomb failure stress,which were triggered by the stress effect of main shocks,Lushan M_S7.0 earthquake might have stress triggering on Xiaojiang Fault and its adjacent western region,for the reason that Eastern Yunnan was on the stress blocking state.

引言
1 构造背景
2 原理和方法
3 资料
4 计算结果
5 结论和讨论

图1 芦山地震M-t图<br/>Fig.1 M-t chart of Lushan MS7.0 earthquakes

图1 芦山地震M-t图
Fig.1 M-t chart of Lushan MS7.0 earthquakes

表1 3个震源模型的主要参数<br/>Tab.1 Main parameters of the three source models

表1 3个震源模型的主要参数
Tab.1 Main parameters of the three source models

表2 区域构造应力场主要参数<br/>Tab.2 Main parameters of regional tectonic stress field

表2 区域构造应力场主要参数
Tab.2 Main parameters of regional tectonic stress field

图2 3个震源模型计算出的芦山地震产生的库仑应力变化与后续地震活动的空间分布(黑色圆点表示研究时段内的地震活动)(a)张勇模型;(b)王卫民模型;(c)刘成利模型<br/>Fig.2 Coulomb stress changes caused by Lushan MS7.0 earthquake based on three source models and spatial distribution of its subsequent seismic

图2 3个震源模型计算出的芦山地震产生的库仑应力变化与后续地震活动的空间分布(黑色圆点表示研究时段内的地震活动)(a)张勇模型;(b)王卫民模型;(c)刘成利模型
Fig.2 Coulomb stress changes caused by Lushan MS7.0 earthquake based on three source models and spatial distribution of its subsequent seismic

表3 滇东地区构造应力场主要参数<br/>Tab.3 Main parameters of tectonic stress field in the east Yunnan areas

表3 滇东地区构造应力场主要参数
Tab.3 Main parameters of tectonic stress field in the east Yunnan areas

图3 芦山地震产生的库仑应力变化对滇东地区影响(矩形框代表小江断裂带位置)(a)以小江断裂带以西地区的构造应力场计算出的应力分布;(b)以小江断裂带以东地区的构造应力场计算出的应力分布<br/>Fig.3 Influence of the coulomb stress changes caused by Lushan MS7.0 earthquake on the east Yunnan areas(the rectangle indicates the location of Xiaojiang Fault)(a)stress distribution calculated by the tectonic stress for the western region to the Xiaojiang Fault;(b)stress distribution calculated by the tectonic stress for the eastern region to the Xiaojiang Fault

图3 芦山地震产生的库仑应力变化对滇东地区影响(矩形框代表小江断裂带位置)(a)以小江断裂带以西地区的构造应力场计算出的应力分布;(b)以小江断裂带以东地区的构造应力场计算出的应力分布
Fig.3 Influence of the coulomb stress changes caused by Lushan MS7.0 earthquake on the east Yunnan areas(the rectangle indicates the location of Xiaojiang Fault)(a)stress distribution calculated by the tectonic stress for the western region to the Xiaojiang Fault;(b)stress distribution calculated by the tectonic stress for the eastern region to the Xiaojiang Fault

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备注

引言

1 构造背景

2 原理和方法

3 资料

4 计算结果

5 结论和讨论

期刊信息