Lanzhou Institute of Seismology, China Seismological Bureau, Lanzhou 730000, China 2) Institute of Geology, China Seismological Bureau, Beijing 100029, China
We have made careful field investigation and trench exploration to the Xishan fault system in west of Urumqi, and an integrated analysis in conjunction with data of deep seismic sounding. Our result suggests that unde...We have made careful field investigation and trench exploration to the Xishan fault system in west of Urumqi, and an integrated analysis in conjunction with data of deep seismic sounding. Our result suggests that under the SN-oriented compressive stress, the Xishan block moves steadily toward the Tianshan Mountains in south, resulting in southward thrust-slip and crustal shortening, particularly the southward thrust of the Xishan fault which serves as the main boundary in south. North of the Xishan fault are the Wangjiagou fault and Jiujiawan fault which are the secondary faults associated with the Xishan fault in generation. Both faults have slippage along horizons during the uplift of the Xishan block, and the Jiujiawan fault has also a component of normal faulting due to the influence of the Bogeda nappe structure. These two faults accommodate the fold deformation of the hanging wall of the Xishan fault, thus the Xishan fault-bounded swell is characterized by monocline. All secondary faults of the Xishan fault system constitute a common seismogenic structural system, so that their seismic hazards should be considered in an equal manner.展开更多
基金State Key Basic Research Development and Programming Project (G19980407-04) and the Project during the ninth Five-Year Plan of Gansu Province (GK973-2-110A).
文摘Lanzhou Institute of Seismology, China Seismological Bureau, Lanzhou 730000, China 2) Institute of Geology, China Seismological Bureau, Beijing 100029, China
基金supported by Active Fault Detection and Earthquake Risk Estimation of Urumqi (1-4-31)Sub-topic of National Science and Technology Support Project (2006BAC13B010102)International Cooperation Key Project of Ministry of Science and Technology "Research on New Methods of Earthquake Prediction and Risk Estimation"(2004BFBA0005)
文摘We have made careful field investigation and trench exploration to the Xishan fault system in west of Urumqi, and an integrated analysis in conjunction with data of deep seismic sounding. Our result suggests that under the SN-oriented compressive stress, the Xishan block moves steadily toward the Tianshan Mountains in south, resulting in southward thrust-slip and crustal shortening, particularly the southward thrust of the Xishan fault which serves as the main boundary in south. North of the Xishan fault are the Wangjiagou fault and Jiujiawan fault which are the secondary faults associated with the Xishan fault in generation. Both faults have slippage along horizons during the uplift of the Xishan block, and the Jiujiawan fault has also a component of normal faulting due to the influence of the Bogeda nappe structure. These two faults accommodate the fold deformation of the hanging wall of the Xishan fault, thus the Xishan fault-bounded swell is characterized by monocline. All secondary faults of the Xishan fault system constitute a common seismogenic structural system, so that their seismic hazards should be considered in an equal manner.
