Study on intermediate focus earthquake belt in Hindukush-Pamirs

摘要

According to the feature of Hindukush-Pamirs intermediate focus earthquake belt with a S-shaped pattern of dipdirection reversion by using the data of earthquake catalogues obtained by seismic networks in Xinjiang and MidAsia area of the former Soviet Union, by means of focal mechanism solution and tectonic stress analysis, it isconsidered that the intermediate focus earthquake belt is possibly formed by the compression rupture which iscaused by the collision between indian and European Plates in the lithosphere of the upper mantle. Under the action of torsion moment, the continuous torsional break of reverse part of the earthquake belt might be the reasonwhy the intermediate focus strong earthquakes occur repeatedly in the same place. In this paper, the boundary linebetween the intermediate focus earthquake belt and the shallow focus earthquake region of the western part ofsouth Tianshan is also defined from the angle of seismicity division.