地震的丛集性与断裂间的相互作用:兼论祁连山东段的地震危险性

EARTHQUAKE CLUSTERING AND FAULT INTERACTIONS:A DISCUSSION ON THE SEISMIC HAZARD IN THE EAST QILIAN MOUNTAINS,CHINA

摘要:

从地震丛集的大量实例出发,讨论了地震丛集与断裂间相互作用的特点、基本规律、机理问题及对地震预测的意义,在此基础上对祁连山断裂带东段的地震危险性进行了定性分析,认为1927年古浪8.0级地震的发生对此区断裂的地震潜势产生深刻影响.它可能暗示:此区内的未来大震与1927年古浪地震分属两个地震丛集期;古浪地震的发生使得作为危险段落的金强河-毛毛山断裂上的挤压应力显著增大,从而延迟了未来大震的发震时间.

Abstract:

Proceeding from actual clustering of earthquakes,the primary characteristics,regularities and mechanism of earthquake clustering and fault interactions as well as their implication to earthquake prediction are discussed.Then the seismic hazard in the east Qilian Mountains is analyzed qualitatively.The occurrence of 1927 Gulang M_S8.0 earthquake deeply affects to the potential of future earthquakes on the faults in this region.It implies that:① future great earthquakes in the region will probably not occur until next earthquake clustering;② the occurrence of the Gulang earthquake increases the compressive stress on the Jinqianghe Maomaoshan fault zone which was believed to be most dangerous,thereby postponing the occurrence of the supposed great earthquake.