临潭-宕昌断裂及附近地区静态库仑应力变化及地震活动性研究

基于Okada的弹性半空间模型，分别计算岷县MS6.6、MS5.2地震和岷县-卓尼MS5.0地震对后续地震的静态库仑应力变化，分析应力扰动对后续地震的影响。结果显示：1）研究区内3次中强地震的共同作用促进了后续地震的发生，后续地震绝大部分位于应力增加区内；2）临潭-宕昌区域背景地震活动性较强，尤其是宕昌及周边地区，地震活动呈条带状展布，与临潭-宕昌断裂走向垂直，研究区整体地震活动性变化以宕昌地区为中心向外呈辐射状减弱；3）岷县段、西段和中段处于应力累积阶段，未来发生强震的可能性较小，宕昌段未来一段时间内地震活动性高于区域背景地震活动性，值得高度关注。

Research on Static Coulomb Stress Changes and Seismicity in Lintan-Tanchang Fault and the Adjacent Area

Based on Okada’s elastic half-space model, the changes of Coulomb stress after the main shock are calculated and the influences of stress disturbance on the subsequent earthquakes are analyzed. The results show that: (1) Three earthquakes in the study area triggered the subsequent aftershocks which are located in areas with ΔCFS＞0. (2) The seismicity of regional background of Lintan-Tanchang is stronger than that of other areas, especially Tanchang and the adjacent areas, and the distribution of earthquakes is perpendicular to the strike of Lintan-Tanchang fault. The value of seismicity in the study area is reduced from central Tanchang to both edges gradually. (3) The seismicity in Tanchang would be higher than the seismicity of local background in the future, which needs our close attention. The seismicity of other regions in this study area are under that of the background, so the possibility of the occurrence of strong earthquakes would be smaller in the future.