天山地震活动区的深部构造特征

以地壳介质的Ｐ波速度分布和导电性为基础，描述了天山地区几个主要地震活动区域深部构造特征，地震大都发生在地壳内不同速度块体之间的过渡带附近；沿着天山的南缘和毗邻塔里木盆地的西昆仑、阿尔金等山前地带，壳内高导层由北向南、由东向西逐渐加深并增厚，它们与所在地区震源深度的分相相吻合。这种不稳定的地壳结构有长期受力情况下非常容易发生形变甚至破裂而引发地震。

DEEP-SEATED TECTONICS IN ACTIVE EARTHQUAKE ZONES OF TIANSHAN

The velocity and conductivity of crustal media were applied to discuss the deep-seated tectonics in several major active earthquake zones of Tianshan. The earthquakes mostly happened at the transitional velocity zones along the southern margin of Tianshan,and piedmont zone of West Kunlun and Altun Mts. near Tarim basin. The intracrustal high-conductvity layers get deeper and thicker gradually from north to south,and from east to west,which corresponds with the distribution of focal depth. The crust of unstable structures will get deformed and fracrtured and even causes earthquakes when it is enforced for a long time.