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| 伽师强震群的深部动力学条件 | |
| 引用本文： | 赵俊猛,卢芳,嘉世旭,徐强,唐伟.伽师强震群的深部动力学条件[J].地震研究,2006,29(4):338-343. |
| 作者姓名： | 赵俊猛 卢芳 嘉世旭 徐强 唐伟 |
| 作者单位： | 1. 中国科学院青藏高原研究所,北京,100085 2. 湖北省地震局,武汉,430071 3. 中国地震局地球物理勘探研究中心,郑州,450002 |
| 摘 要： | 根据天山造山带及其两侧的塔里木盆地和准噶尔盆地的岩石圈二维速度结构、二维密度结构、二维电性结构、壳幔过渡带的详细结构以及大地热流和震源深度的分布，再结合对新疆西北部的蛇绿岩带、高压变质带和岩浆岩分布的综合分析，建立了天山造山带的地球动力学“层间插入消减”模型。该模型认为，塔里木板块的中上地壳在库尔勒断裂附近向天山造山带的中下地壳层间插入；而下地壳连同岩石圈地幔向天山造山带的上地幔俯冲消减。在天山的西段（哈萨克斯坦境内），费尔干纳地块由北向南插入到南天山之下约180km的深处，在其东段（中国境内），塔里木盆地由南向北插入南天山之下。这两个具有不同方向的下降板片的接触部位为费尔干纳走滑断裂。我国的伽师、喀什、乌恰地震区均落在这两个具有不同俯冲方向板块的结合部位附近，有着特殊的深部构造背景。南、北两大板块的双向挤压必定产生强大的应力，在地震区附近，这种应力的积累与释放具有4个显著的特点：（1）板片的俯冲消减速度约高达每年22mm左右；（2）应力的积累与释放速率加快；（3）应力释放较容易；（4）应力释放较为集中。这4个特点可能是伽师地区在较短的时间内连续发生数次强震的构造因素。 |
| 关 键 词： | 天山造山带 层间插入消减模型 走滑断裂 伽师强震群 |
| 文章编号： | 1000-0666-(2006)04-0338-06 |
| 收稿时间： | 2005-12-26 |
| 修稿时间： | 2005年12月26 |
Deep Geodynamic Conditions for the Jiashi Strong Earthquake Swarms |
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| ZHAO Jun-meng,LU Fang,JIA Shi-xu,XU Qiang,TANG Wei.Deep Geodynamic Conditions for the Jiashi Strong Earthquake Swarms[J].Journal of Seismological Research,2006,29(4):338-343. | |
| Authors: | ZHAO Jun-meng LU Fang JIA Shi-xu XU Qiang TANG Wei |
| Institution: | 1. Institute of Tibetan Plateau Research, CAS, Beijing 100085, China;2. Seismological Bureau of Hubei Province, Wuhan 430071, China;3. Center for Geophysical Exploration, China Seismological Bureau, Zhengzhou 450002, China |
| Abstract: | Based on the 2D velocity structure, 2D density structure, 2D electrical structure, detailed structure of crust-mantle transitional zone, the distribution of heat flow and focal depths,the distribution of ophiolite suites, high pressure metamorphic belts and the magmatic rock in Northwestern Xinjiang, China, a geodynamic model of lithospheric subduction with intrusion of layers into the crust was established for the Tienshan orogenic belt, Tarim basin and Junggar basin. The main points are that middle and upper crust of the Tarim basin intruded into the lower and the middle crust of the Tienshan orogenic belt and the lower crust and the lithospheric mantle of the Tarim basin subducted into the upper mantle of the Tienshan orogenic belt. In western Tienshan (in Kazakstan), the Fergana block inserted the depth of 180 km beneath South Tienshan southward. Both fallen blocks with opposite directions met in the Fergana strike-slip fault. Located at South Tienshan, the Jiashi, Kashi and Wuqia seismic zones fall actually at a boundary of the two subducting slabs with opposite directions, forming a special deep tectonic setting. A strong stress must be generated under the two-direction compression. The accumulation and release of the stress bear the following features: the relative speed of the two subducting slabs is more than 22 mm/y; the speed of stress accumulation and release are accelerated; the stress can be easily released; and the stress release is concentrated. The features mentioned above may be the deep tectonic conditions for Jiashi strong earthquake swarms. |
| Keywords: | Tienshan orogenic belt model of lithospheric subduction with crust intrusion strike-slip fault Jiashi strong earthquake swarm |
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