昆仑山口西8.1级地震前的地震活动图像演变特征

EVOLUTION CHARACTERISTICS OF SEISMICITY PATTERN BEFORE WEST TO KUNLUN MOUNTAIN PASS M_S8.1 EARTHQUAKE

昆仑山口西8.1级地震的孕育过程以地震空间图像的递进演变为特征,可分为三个阶段:1959年以来M≥6地震围成背景空区的阶段,1994年以来M≥5地震围成孕震空区的阶段和震前4个月的"逼近地震空区"阶段.在孕震空区的末期,青藏块体及中国西部出现了1～2年的地震条带;伴随逼近地震空区的形成,还出现了较大范围的小震平静.最后讨论了中国大陆西部8级地震的时空演变特征.

Seismogenic process of west to Kunlun Mountain Pass MS8.1 earthquake is consists of three evolutionary stages for seismicity pattern.The first stage is background gap formed by MS≥6 earthquake from 1959;the second stage is pregnant gap formed by MS≥5 earthquakes from in 1994, and the third stage,'imminent earthquake gap' lasts 4 months before the MS8.1 earthquake.At the later period of the pregnant gap,seismic bands in 1～2 years appeared in Qinghai-Xizang block and western China. Along with the formation of the 'imminent earthquake gap', no small earthquake occurred in the region.The timespace evolutionary feature of MS8 earthquakes in western China is discussed at the end.