This paper makes a systematical study on characteristics of structure and motion of the tectonic blocks in northern part of the Shanxi fault depression zone by means of geometrical and kinematical analysis of the bloc...This paper makes a systematical study on characteristics of structure and motion of the tectonic blocks in northern part of the Shanxi fault depression zone by means of geometrical and kinematical analysis of the blocks. The ki-netic behavior of the blocks is discussed by comparing associated geomorphic features of fault movement. All analyses and studies are based on a Domino model. The block movement, fault basin extension and their regional distribution are systematically investigated. The result shows: (a) The studied region is divided into sub-regions by NW striking faults: the western, middle and eastern sub-region with crustal extension being 4.46 km, 2.80 km and 1.86 km, respectively. The extensional amount of each block in the region is estimated being generally about 1 km. The calculated result using the block motion model approximately fits the data of geologic survey. (b) Block kin-ematical features are obviously different between the northern and southern part, with the Hengshan block in be-tween, of the studied region. Moreover, the magnitude of the largest historical earthquake in the northern part is about 6, while that in the southern is 7. The faulted blocks in the northern sub-region show northwestward exten-sion, indicating a feature of extensional graben, while the blocks in the southern part manifest tilt motion, extend-ing southeastward, in the opposite sense of fault dipping. Additional tectonic stress generated by block rotation may be one of major factors affecting seismogenic process in the region. It is responsible for the difference in the movement of the block boundary faults and seismic activities between the two sub-regions.展开更多
The Bayan Har block is mainly bounded by the east Kunlun fault zone to the north, Garze-Yushu -Xianshuihe fault zone to the south and Longmenshan fault zone to the east （Fig. 1）. In the past 20 years, large earthqua...The Bayan Har block is mainly bounded by the east Kunlun fault zone to the north, Garze-Yushu -Xianshuihe fault zone to the south and Longmenshan fault zone to the east （Fig. 1）. In the past 20 years, large earthquakes have occurred frequently along this block＇s boundaries, which has received much attention among geoscientists. Whether large earthquakes will happen （and where） along this block＇s boundary faults in the future are two key problems that need to be addressed. This study calculates the accumulated tectonic stress and superposition of the coulomb stress caused by fault slip of 16 large earthquakes since 1904, and evaluates the possible locations of future earthquakes that may occur around this block.展开更多
文摘This paper makes a systematical study on characteristics of structure and motion of the tectonic blocks in northern part of the Shanxi fault depression zone by means of geometrical and kinematical analysis of the blocks. The ki-netic behavior of the blocks is discussed by comparing associated geomorphic features of fault movement. All analyses and studies are based on a Domino model. The block movement, fault basin extension and their regional distribution are systematically investigated. The result shows: (a) The studied region is divided into sub-regions by NW striking faults: the western, middle and eastern sub-region with crustal extension being 4.46 km, 2.80 km and 1.86 km, respectively. The extensional amount of each block in the region is estimated being generally about 1 km. The calculated result using the block motion model approximately fits the data of geologic survey. (b) Block kin-ematical features are obviously different between the northern and southern part, with the Hengshan block in be-tween, of the studied region. Moreover, the magnitude of the largest historical earthquake in the northern part is about 6, while that in the southern is 7. The faulted blocks in the northern sub-region show northwestward exten-sion, indicating a feature of extensional graben, while the blocks in the southern part manifest tilt motion, extend-ing southeastward, in the opposite sense of fault dipping. Additional tectonic stress generated by block rotation may be one of major factors affecting seismogenic process in the region. It is responsible for the difference in the movement of the block boundary faults and seismic activities between the two sub-regions.
基金supported by Geological Survey programs from Geological Survey of China(No.1212011120163 and 12120114002101)Basic Science Research Fund of the Institute of Geomechanics,CAGS (No.DZLXJK201212)National Natural Science Foundation of China (No.41171009)
文摘The Bayan Har block is mainly bounded by the east Kunlun fault zone to the north, Garze-Yushu -Xianshuihe fault zone to the south and Longmenshan fault zone to the east （Fig. 1）. In the past 20 years, large earthquakes have occurred frequently along this block＇s boundaries, which has received much attention among geoscientists. Whether large earthquakes will happen （and where） along this block＇s boundary faults in the future are two key problems that need to be addressed. This study calculates the accumulated tectonic stress and superposition of the coulomb stress caused by fault slip of 16 large earthquakes since 1904, and evaluates the possible locations of future earthquakes that may occur around this block.
