地震学报（英文版）2005，Vol.18Issue(2)：125-134,10.
The heterogeneous characteristics of crust-mantle structures and the seismic activities in the northwest Beijing region
The heterogeneous characteristics of crust-mantle structures and the seismic activities in the northwest Beijing region
摘要
Abstract
In this paper, the abnormal characteristics of the crustal structures in the seismic active region, Yanqing-Huailai and Zhangbei-Shangyi, are obtained by means of comprehensively interpreting and studying the data of deep seismic sounding profiles passing through the northwestern part of Zhangjiakou-Bohai seismic zone. The results show that the fluctuation of crystalline basement in the study region is obvious and that there exist considerable differences in depth in different geological units. The locally abrupt variation of crystalline basement depths may be regarded as a mark of existence of crystalline basement faults. These crystalline basement faults and deep crustal faults provide a pass for the magma upwelling, resulting in the strong inhomogeneity of crustal structures. These phenomena of the complex seismic reflected waves and locally discontinuous reflection zones with different energy indicate that the intensive squeeze and deformation of crust took place, which have led to the complex crustal structures and offered the dynamic source for the earthquake occurrence in this region. The low velocity bodies in different depths of crust and the local interface C1 in Zhangbei-Shangyi region may result from repeated magmatic activities. The certain stress accumulation in the brittle upper crust can cause the occurrence of earthquake under the action of local tectonic activity.关键词
northwest Beijing region/seismic sounding/shallow and deep structures/earthquake-generating backgroundsKey words
northwest Beijing region/seismic sounding/shallow and deep structures/earthquake-generating backgrounds分类
天文与地球科学引用本文复制引用
ZHAO Jin-ren,ZHANG Xian-kang,ZHANG Cheng-ke,ZHANG Jian-shi,LIU Bao-feng,REN Qing-fang,PAN Su-zhen,HAI Yan..The heterogeneous characteristics of crust-mantle structures and the seismic activities in the northwest Beijing region[J].地震学报（英文版）,2005,18(2):125-134,10.基金项目
National Natural Science Foundation of China (40334040) and Key Project from China Earthquake Administration during the ninth Five-year Plan (9504080101). （40334040）
