| 2008年新疆乌恰6.8级地震序列震源特征及帕米尔东北缘应力场研究 |
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| 引用本文： | 唐兰兰,赵翠萍,王海涛.2008年新疆乌恰6.8级地震序列震源特征及帕米尔东北缘应力场研究[J].地球物理学报,2012,55(4):1228-1239. |
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| 作者姓名： | 唐兰兰 赵翠萍 王海涛 |
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| 作者单位： | 1. 新疆维吾尔自治区地震局, 乌鲁木齐 830011;
2. 中国地震局地震预测研究所, 北京 100036 |
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| 摘 要： | 本文使用新疆区域数字地震台站记录的宽频带长周期数字波形资料,在时间域反演了2008年10月5日新疆乌恰6.8级地震的强余震及其周围先后发生的52次中等强度地震的矩张量解,结合Harvard大学在该区域的地震矩张量结果,研究了帕米尔东北缘的应力场分区特征.研究结果显示,位于印度板块向欧亚板块推挤的前缘及向北凸出的弧型构造的最北缘的卡兹克阿尔特弧形活动褶皱-逆断裂带,以逆冲推覆活动为主,并有部分走滑类型的地震,基本不存在正断层类型的地震;该弧型构造近东西走向的顶部(文中的西区)与其北西走向的东侧(文中的东区)的局部应力场最大主压应力方向不同,分别为NW、NNE方向,显示出在承受印度板块向欧亚板块俯冲作用的同时,东区也更多的受到了塔里木块体顺时针旋转作用的影响.位于帕米尔陆内俯冲和变形作用强烈、碰撞造成深源地震带东段的南区,地震以走滑错动为主, 逆断、正断层都有,显示出相对复杂的应力状态.位于帕米尔高原内部的西区和南区的应力场最大主压应力方向一致,由北向南,由最大主压应力轴接近水平,过渡为最大主张应力轴接近水平,一定程度揭示了板块俯冲的状态.结合南区和西区的地震深度差异及机制解中断层面的倾角,推测在中帕米尔的东部,由北向南的板块俯冲至150~170km深度,俯冲角度为60°左右.
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| 关 键 词： | 帕米尔地区 地震矩张量反演 应力场特征 |
| 收稿时间： | 2011-05-05 |
Study on the source characteristics of the 2008 Ms6.8 Wuqia, Xinjiang earthquake sequence and the stress field on the northeastern boundary of Pamir |
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| TANG Lan-Lan
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ZHAO Cui-Ping
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WANG Hal-Tao.Study on the source characteristics of the 2008 Ms6.8 Wuqia, Xinjiang earthquake sequence and the stress field on the northeastern boundary of Pamir[J].Chinese Journal of Geophysics,2012,55(4):1228-1239. |
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| Authors: | TANG Lan-Lan ZHAO Cui-Ping WANG Hal-Tao |
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| Institution: | 1. Seismological Bureau of Xinjiang Uygur Autonomous Region, Urumqi 830011, China;
2. Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China |
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| Abstract: | Moment tensor solutions of 52 earthquakes occurred in the 2008 MS6.8 Wuqia source region,Xinjiang,were estimated in time domain by using the long period waveforms recorded by the regional broadband stations.Then combined with the Harvard solutions,the characteristic of stress field in northeastern margin of Pamir are studied.The result reveals that overthrusting is the main pattern on the curved Kazkeaerte active reverse fault fold zone,which is located in front of the collision zone between Indian plate and Eurasian plate,as well as the northern edge of the northward bulge arc structure.And there are also a few strike-slip faults,normal fault almost does not exist.The trend of the local maximum principal stress is different on the top of the arc(the western region in the paper) and the eastern boundary(the eastern region in the paper),which is NNE and NNW respectively,suggesting the influence of clockwise rotation of Tarim block,while the whole Pamir undergoing the force of the India plate crushing to the Eurasian plate.The types of focal mechanism solutions in the southern region,which is located on the eastern section of Pamir deep seismic zone formed by intensive collision,subduction,and deformation process,are mainly strike-slip,and with some normal and reverse faults as well.The trending of the principal compressive stress in western and southern Pamir is the same,but the dip angle in western region is horizontal and the principal tensional stress in the southern region is horizontal,which may reveal that the subduction depth of the Eurasian continental lithosphere in the eastern region of central Pamir is about 150 to 170km deep and the subducting angle is about 60°. |
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| Keywords: | Pamir region Seismic moment tensor inversion Stress field features |
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