首都圈地区震源机制解综合研究

Comprehensive research on focal mechanism solutions in the Capital Area

摘要:

对首都圈地区2002年1月～2010年6月619个ML≥2.0地震的震源机制解的基本特征进行了统计分析,并且依据区域构造特征将首都圈划分为3个区域,用聚类统计方法中的最长距离法对各分区的机制解进行了聚类分析,研究了各分区的构造应力张量特征。研究结果表明,首都圈地区震源机制解P轴方位的优势分布为NNE-NEE向,T轴方位的优势分布为NNW-NWW向,绝大多数地震震源处的应力场以水平作用为主,破裂以水平走滑为主。首都圈西部最大主压应力方位为NE75°,中部最大主压应力方位为NE62°,东部最大主压应力方位近EW向,区域构造应力场以水平向挤压为主要特征。

Abstract:

A comprehensive statistical analysis was made on the basic features of focal mechanism solutions of 619 ML≥2. 0 quakes from January, 2002 to June 2010 in the Capital Area which was divided into three studying regions in terms of regional tectonic characteristics. The paper conducted a clustering analysis on focal mechanisms of all partitions using the longest distance method of clustering statistical, and studied the characteristics of tectonic stress tensor. The result shows that advantage distribution of P-axis is NNE-NEE and T-axis is NNW-NWW. Most of the hypocentrals are mainly horizontal stress action. Rupture is mainly horizontal strike-slip. The maximum principle compressional stress orientation is NET5° in the west of the Capital Area, NE62° in the middle of the Capital Area, and near EW in the east of the area. The main characteristic of the region tectonic stress field is of horizontal extrusion.[著者文摘]