摘要
本文利用川滇地区1980—2013年震级M2.2—5.9的12924条地震资料,对该地区进行了精细b值计算;利用川滇地区321个M≥4.7的中强地震震源机制解资料,结合b值的空间分布特征,划分震源区,并探讨了不同类型震源区b值的变化规律。研究结果显示:川滇地区b值分布存在较大差异,川滇菱形块体的东边界和西南边界的低b值范围较大,菱形块体内部高b值区域相对集中,研究区内其余地区的b值分布较为零散;结合我国现行的地震区带划分方案,b值分布没有表现出带内的一致性;结合地震的震源机制,倾滑断层型的地震表现出逆断型震源区地震的b值低于正断型震源区内同类型地震的b值。这将为b值统计单元的划分提供有益的参考。
High resolution b values in the Sichuan-Yunnan area were calculated from 34-year instrumental earthquake data. Based on the analysis of focal mechanism of 321 earthquakes with M≥4.7, eight typical seismic source zones were divided in the study area. Combining with the distribution of b-value, we studied the varying law of b-value with different type of focal mechanism. Three conclusions are obtained as follows. First of all, the results of b-value varies dramatically over the study are. Low b values mainly show at the east and southwest margins around the Sichuan-Yunnan Rhombic block, whereas high b values show inside the block. Secondly, combining with the seismic zones, the results of b-value are not in the consistency within the one zone. Thirdly, based on the data of focal mechanism, the b-value of thrust earthquakes is apparently lower than that of normal earthquakes. Our results could be used as a reference to the division of statistic unit for b-value calculation.
出处
《震灾防御技术》
CSCD
北大核心
2016年第3期561-572,共12页
Technology for Earthquake Disaster Prevention
基金
中国地震局地壳应力研究所中央级公益性科研院所基本科研业务专项(ZDJ2016-03)资助
关键词
川滇地区
B值
震源机制
震源类型
Sichuan-Yunnan area
b-value
Focal mechanism
Type of seismic source
