阿尔金地区构造应力场研究

用软材料和激光全息光弹模拟实验方法,分析了阿尔金地区现代构造应力场的特征和在区域应力场作用下阿尔金断层的活动规律以及大震前后震区应力场的调整情况,结果表明:阿尔金地区现今构造应力场主压应力轴近南北向,南边印度板块向北推进的过程中,使得青藏高原西北边界的阿尔金断裂各段的活动性质和滑移速度不同。东西两段左旋位移较明显;中段呈明显压性;应力集中区分布在一些特殊构造部位。模拟大震应力释放反映,大震后震中区附近剪应力值迅速下降,周围一些地区的剪应力值升高,形成未来地震危险区。

STUDY ON THE TECTONIC STRESS FIELD IN ALJIN AREA

In this paper,the characteristics of recent tectonic stress field in Aljin area has been analyzed by the test method of soft materials and laser holographic photoelastic model. Under the force of regional stress field, active patterns of Aljin fault and the adjustment movement of stress field in the earthquake regions around great shocks were varied. Results show that in Aljin area,the principal axis of compressive stress in the recent tectonic stress field is in near northsouth direction. Affected by Indian plate moving northward, the Aljin fracture showed different moving features and sliding speeds at each segments. Sinistral displacements are found at east and west segments,but an obvious compressive structure is at middle segment, stress is mainly concentrated at some special tectonic parts. Stress release for simulated earthquakes indicates that the shear stress values decreased quickly in the epicentral region after large earthquake occurrence, and while in the surrounding areas they increased much,in which a future seismic risk region is formed.