摘要
本文利用有关作者对中国及四川地壳和上地幔速度结构的研究成果,根据《四川地震台网观测报告》(1982—1988年),挑选出震中落在四川紫坪铺(ZPPS)区域内(29.5—32.5°N,102—105°E)的M_L≥2.0,且精度在C类以上的小地震的初动符号,然后分4个工作区,分别求其平均应力场。结果表明,虽然这4个工作区内的平均应力场比较复杂,但其P轴却都接近水平,而且每个工作区内的平均应力场又都与各该区内较大地震的发震应力场比较一致。此外,这4个工作区的构造形变似乎也有规律性的变化。
By using the research results on velocity structure of the crust and upper mantle in China and Sichuan province, the first motion signs of small earthquakes (M≥2.0, rank: a, b and c), whose epicenters are located in Zipingpu area, Sichuan province (29.5-32.5-N, 102°-105° E), are selected from 《Bulletin of Seismological Observation of Sichuan Stntions》 (1982-1988). Then, the area is divided into 4 working regions, and the mean stress fields are separately obtained. The results show that their P axes, are all nearly horizontal and the mean stress field for each working region is consistent with the seismogenetic stress of larger earthquakes in the same region, although the mean stress field is more complicated. Besides, tectonic deformation of 4 working regions is regularly changed.
出处
《地震》
CSCD
北大核心
1993年第1期10-15,共6页
Earthquake
关键词
地壳构造
地震
应力场
构造形变
crustal structure
first motion of small earthquakes
mean stress field
rectonic deformation
