地震前后断层测点群体活动的量化指标  

QUANTITZED INDEX OF SWARM MOVEMENT OF OBSERVATION SITES IN FAULTS BEFORE AND AFTER EARTHQUAKE

作　　者：张四新[1] 王双绪[1] 刘文义[1] 郑申宝[1] 

机构地区：[1]中国地震局第二监测中心,西安710054

出　　处：《大地测量与地球动力学》2006年第2期53-57,共5页Journal of Geodesy and Geodynamics

基　　金：地震科学联合基金(104011)

摘　　要：地震前后,随着构造应力场的增强或减弱,断层测点群体偏离稳态变化的程度随之增大或减小;同时,由于震源体内外介质物性的差异,断层测点之间偏离稳态变化的差异性也随之增大或减小。基于这一事实,采用随机变量的数字指标,提出了一种反映断层群体活动的量化指标——断层活动强度及非均匀度。结合具体震例对青藏块体东北部、川滇地区的断层水准资料进行了计算,结果表明量化指标在地震前后一般会出现一个明显的增大或减小过程。The degree that the swarm movement of measurement sites of cross-faults devia creases or decreases along with strengthening or weakening of tectonic stress field before and tes from stability, inafter earthquake. At the same time, the difference of deviation from stability among the measurement sites increases or decreases due to the difference between internal and external medium characteristic of the source body. On the basis of the fact, a quantized index of swarm sites movement of faults--the average strongth and the non-homogeneity of fault movement with the numeric index of random variable is put forward. By calculating the vertical deformation data of crossfaults in Sichuan-Yunnan area and the northern margin of Qinghai-Tibet block, and comparatively studying some practical earthquake examples, the results are obtained： the quantized index increases or decreases obviously before and after earthquake.

关 键 词：地震 断层测点 群体活动 断层形变 量化指标 

分 类 号：P315.725[天文地球—地震学]