Basic Characteristics of Active Structures in Western Sichuan and Its Vicinity and Strong Earthquake Recurrence Model  

作　　者：Xu Xiwei Zhang Peizhen Wen Xueze Qin Zunli Chen Guihua Zhu Ailan 

机构地区：[1]Institute of Geology, China Earthquake Administration, Beijing 100029, China [2]Earthquake Administration of Sichuan Province, Chengdu 610041, China [3]Beijing Guodian Water Conservancy and Electrical Engineering Co. Ltd., Beijing 100024, China

出　　处：《Earthquake Research in China》2006年第1期75-89,共15页中国地震研究（英文版）

基　　金：ThisprojectwassponsoredbytheNationalKeyBasicResearchProject(2004CB418401)andtheStateScienceandTechnologicalKeyBasicProgram(2003DIA6N005);China.

摘　　要：Western Sichuan and its vicinity are located in the juncture of three big active blocks, namely, the Chuandian （Sichuan and Yunnan）, the Bayan Har and the South China blocks, on the eastern margin of the Qinghai-Xizang（Tibet） Plateau. Many groups of active faults that are capable of generating earthquakes are developed there. Because there exist lateral secondary active faults, the Chuandian block can be further divided into the central Yumlan and northwestern Sichuan sub-blocks; while the Longmenshan sub-block can be divided on the east end of the Bayan Har block. Joint exploration of deep crustal structure shows that there exist low-velocity and high-conductivity layers in the crust of the Chuandian and Bayan Har blocks, which are one of the important factors that make the upper crust prone to earthquake. The results of geological study and modern GPS observation show that blocks of different orders all have SE- or SSE-trending sliding, clockwise rotation and upwelling movement; but there are some differences in amplitude. This paper has also given the geological or GPS slip rates of main active fault zones and discussed the main scientific problems still existing now.Western Sichuan and its vicinity are located in the juncture of three big active blocks, namely, the Chuandian (Sichuan and Yunnan), the Bayan Har and the South China blocks, on the eastern margin of the Qinghai-Xizang(Tibet) Plateau. Many groups of active faults that are capable of generating earthquakes are developed there. Because there exist lateral secondary active faults, the Chuandian block can be further divided into the central Yunnan and northwestern Sichuan sub_blocks; while the Longmenshan sub_block can be divided on the east end of the Bayan Har block. Joint exploration of deep crustal structure shows that there exist low-velocity and high-conductivity layers in the crust of the Chuandian and Bayan Har blocks, which are one of the important factors that make the upper crust prone to earthquake. The results of geological study and modern GPS observation show that blocks of different orders all have SE-or SSE-trending sliding, clockwise rotation and upwelling movement; but there are some differences in amplitude. This paper has also given the geological or GPS slip rates of main active fault zones and discussed the main scientific problems still existing now.

关 键 词：Western Sichuan Active tectonics Active block Strong earthquake recurrence model 

分 类 号：P315.5[天文地球—地震学]