摘要
文中利用三峡加密观测台网记录的2009年3月到2010年12月高精度地震数据,使用双差层析成像方法,联合反演了三峡库区上地壳的震源位置参数和三维上地壳P波和S波速度结构。研究结果显示,三峡库区上地壳P波速度和S波速度区域出现2个高VP值、上低下高VS值区,分别在巴东北部神农溪两岸—泄滩西区域和仙女山断裂带北段香溪河口附近。巴东北部神农溪两岸—泄滩西区域,较小地震的平面分布呈3条近EW向的条带,剖面陡立、向N倾,沿着P波和S波高、低速过渡带分布;香溪河口附近地震沿NNW向的仙女山断裂带分布,地质剖面显示出地震陡立线性分布,沿着高VP值、上低下高VS值区的过渡带展布,联合反演得到的微震面与断裂构造分布具有较好的一致性。
In this paper,using the double difference tomography method,the P wave and S wave velocity structures of the earth＇s crust beneath the Three Gorges Reservoir are inversed based on the highresolution seismic data of seismological stations recorded from March 2009 to December 2010.According to the research results,the P wave and S wave crust velocity zones in the Three Gorges Reservoir area show a high VPvalue area and a VSvalue area with value low in the lower part and high in the upper part,distributing respectively at both sides of Shennongxi River to western Xietan in the north of Badong and near the outlet of the Xiangxi River at the northern section on Xiannvshan Fault.In the region from the two sides of Shennong River in the north of Badong to the western Xietan,microseisms are distributed in three zones in near east-west direction,with steep and north-dipping sections,spreading along the high- to- low velocity transition zone of the P and S wave. On the northern section of Xiannvshan Fault,small earthquakes are distributed along the NNW-trending Xiannvshan Fault, and the geological section reveals a steep and linear distribution along the transitional zone between the high VPvalue area and the VSvalue that is low in the upper and high in the lower part. Joint inversion results show a good consistency of the planes of the microseisms with the distribution of active faults.
出处
《地震地质》
EI
CSCD
北大核心
2016年第2期329-341,共13页
Seismology and Geology
基金
中国地震局2015年度全国地震监测常规任务(272)
“十一五”国家科技支撑重点课题(2008BAC38B04)共同资助
关键词
双差层析成像
P波速度
S波速度
上地壳构造
三峡水库
double difference tomography
P and S-wave velocity structure
upper crust structure
Three Gorges Reservoir
