四川区域地震台网的剪切波分裂研究  

A study on S wave splitting using waveform data from Sichuan Regional Seismic Network

作　　者：张永久[1] 高原[2] 石玉涛[2] 程万正[1] 

机构地区：[1]四川省地震局,中国成都610041 [2]中国地震局地震预测研究所,中国北京100036

出　　处：《地震学报》2008年第2期123-134,216,共12页Acta Seismologica Sinica

基　　金：中国地震局地震预测研究所基本科研专项(2007-24)资助

摘　　要：通过对成都数字地震台网2000年5月1日—2006年12月31日6年多资料的分析,使用剪切波分裂SAM系统分析方法,获得了四川地区8个地震台站的快剪切波偏振结果.结果表明,四川地区大部分台站的快剪切波偏振优势方向主要为NE或NW方向;位于活动断裂上或几条活动断裂交汇部位的台站的快剪切波偏振优势方向,大多数与对选用的小地震起控制作用的活动断裂走向一致,或与区域主压应力方向一致.但复杂的局部构造会影响剪切波分裂结果,造成台站的快剪切波偏振优势方向与主要活动断裂走向不一致,或与区域主压应力相差较大的现象.Using seismic data recorded by the Chengdu Digital Seismic Network from May 1, 2000, to December 31, 2006, and the SAM technique for S wave splitting analysis, this study has found the dominant polarization directions of fast S wave at 8 stations. The result shows that the dominant polarization directions at most stations are mainly in nearly NE-SW or NW-SE in Sichuan region. The dominant polarization direction at the stations located on active faults or at the intersection of several active faults is consistent with the strike of the faults, which control the earthquakes used in this analysis, and is basically consistent with the direction of regional compression axis. However, for some stations the fast S wave polarization directions are not consistent with the fault strikes and the directions of regional compression axis, probably owing to the influence of local complicated crustal structure.

关 键 词：剪切波分裂 快剪切波偏振 主压应力 活动断裂 四川地区 

分 类 号：P315.31[天文地球—地震学]