Abstract: Jiashi and its surrounding areas are composed of many structural zones.Using the focal mechanism solutions of 59 mid-strong earthquakes in Jiashi and its surrounding areas,and combining with the calculation result of system cluster and stress field inversion,we analyzed the evolvement characteristics of the stress field for the different times and the different regions.The result shows as follows:The earthquakes in Jiashi are mainly of strike-slip.However,those of Kalpin block are mainly of reverse events,showing an obvious thrusting.The regional characteristics are different from other areas.The direction of the regional principal stress field is near NS.However,under the different tectonic background,the directions of stress fields are different.The direction of the principal compression stress is near NS in Kashi-Wuqia area.But before and after the 3 earthquakes with M 7,the dynamic evolution from NW to NS and then to NE with time process was observed.Kalpin block has been dominated by the consistent stress field of the NW direction for a long time.However,the direction of the stress field of Jiashi region is NE.From 1996,the direction of the regional stress field has changed obviously.The direction of the P axis was deflected towards NE,and the elevation angle increased.The result shows clearly the regional characteristic and variation of distribution pattern of stress field in different tectonic environments.

Key words: Jiashi and its surrounding areas, focal mechanism solution, tectonic stress field, regional characteristics

摘要： 在利用伽师及周围58次中强地震震源机制解对这一地区的构造应力场进行分析的基础上,结合系统聚类和应力场反演计算结果,对不同时期、不同区域应力场的变化特征进行了分析。该区域地震以走滑错动为主,柯坪块体逆冲作用更为明显。区域最大主压应力方向近SN,但不同构造背景下的主压应力方向存在着较明显的差异。乌恰-喀什地区P轴基本近SN向,但存在着由NW—SN—NE的随时间变化的过程;柯坪块体内部长期以来受较为一致的NW-SE向压应力作用;伽师震区P轴方向为NE-SW。1996年区域应力场方向开始发生明显的变化,P轴方位向NE偏转,倾角增大。结果表现出不同构造环境下应力场分布格局的特征或变化。

关键词: 震源机制, 构造应力场, 区域特征, 伽师及其周围