| 伽师强震群区震源细结构的深地震反射探测研究 |
| |
| 引用本文： | 杨卓欣,张先康,嘉世旭,刘保金,酆少英,赵成斌,潘纪顺.伽师强震群区震源细结构的深地震反射探测研究[J].地球物理学报,2006,49(6):1701-1708. |
| |
| 作者姓名： | 杨卓欣 张先康 嘉世旭 刘保金 酆少英 赵成斌 潘纪顺 |
| |
| 作者单位： | 中国地震局地球物理勘探中心，郑州 450002 |
| |
| 基金项目： | 中国地震局资助项目，国家自然科学基金，中国地震局地球物理勘探中心项目 |
| |
| 摘 要： | 穿过伽师强震群的深地震反射剖面提供了研究区从地表直至莫霍界面的地壳细结构图像.探测结果表明：研究区上、下地壳分界面埋深约20～30 km，莫霍界面埋深约52～58 km.上地壳内部存在着两种截然不同的反射图像.上地壳上部为沉积盖层，厚度约8～9 km，盖层内部反射成层分布，显示了稳定而连续的沉积特点；上地壳下部则为“反射透明”背景下存在的叠层状反射带.下地壳内部呈现明显的反射性质，具体体现在上、下地壳分界面和莫霍间断面都表现为具有一定持续时间的多循环反射叠层结构特征.时间剖面上所有反射事件由北东向南西下倾的整体图像直观地反映了塔里木盆地地壳变形而向西昆仑下插入的事实.剖面47km桩号附近，上地壳下部至壳幔过渡带以上地壳范围内存在一条高倾角的深断裂，具有走滑性质，本研究认为该深断裂与1997年伽师强震群的发生密切相关，推断它为伽师强震群的发震构造.而时间剖面上壳幔过渡带反射的连续性则说明该断裂没有向下穿过莫霍面.存在于上地壳上部的两条高倾角的浅部断层可能对应于地质推测的麦盖提—下苏洪断裂带，它们与位于其下方的地壳深断裂构成了伽师强震群可能的深、浅构造关系.
|
| 关 键 词： | 伽师强震群 深地震反射 震源细结构 |
| 文章编号： | 0001-5733（2006）06-1701-08 |
| 收稿时间： | 2006-06-18 |
| 修稿时间： | 2006-06-182006-07-25 |
Fine crustal structure in the Jiashi earthquake swarm region revealed by deep seismic reflection profiling |
| |
| YANG Zhuo-Xin,ZHANG Xian-Kang,JIA Shi-Xu,LIU Bao-Jin,FENG Shao-Ying,ZHAO Cheng-Bin,PAN Ji-Shun.Fine crustal structure in the Jiashi earthquake swarm region revealed by deep seismic reflection profiling[J].Chinese Journal of Geophysics,2006,49(6):1701-1708. |
| |
| Authors: | YANG Zhuo-Xin ZHANG Xian-Kang JIA Shi-Xu LIU Bao-Jin FENG Shao-Ying ZHAO Cheng-Bin PAN Ji-Shun |
| |
| Institution: | Center of Exploration Geophysics, China Earthquake Administration, Zhengzhou 450002, China |
| |
| Abstract: | Deep seismic reflection profiling across Jiashi strong earthquake swarm region has revealed fine crustal images through to M_discontinuity of the studied area. The result shows that the boundary between the upper and lower crust in this area is about 20～30 km deep and M_discontinuity is about 52～58 km deep. Two completely different types of reflected images appear within the upper crust. The upper part of the upper crust is a stratified 8～9 km deep sedimentary cover, suggesting stable and continuous sedimentation, while the lower part of the upper crust oppears as a laminated reflecting layer against a background of “reflection transparency". The lower crust shows obvious reflectivity, characterized by multi_iteration laminated reflection of the boundary between the upper and lower crust as well as M_discontinuity. All the reflectors dipping downward from northeast to southwest on the CDP section visually reflect crustal deformation of Tarim Basin which thrusts downwards into west Kunlun Mts. Near post 47km there is a high dip angle fault stretching from the lower part of the upper crust to the top of the crust_mantle transitional zone. This strike_slip fault has a direct bearing on the occurrence of the Jiashi strong earthquake swarm and is an inferred causative fault for the swarm (1997) according to this study. However, the continuity of reflection from the crust_mantle transitional zone suggests that the fault does not stretch downwards to disrupt M_discontinuity. The two shallow faults with high dip angle in the upper part of the upper crust may correspond to the geologically inferred Markit_Xiasuhong fault zone. These two faults and the crustal fault below them jointly constitute a possible shallow deep structure relationship for the Jiashi strong earthquake swarm. |
| |
| Keywords: | Jiashi strong earthquake swarm Deep seismic reflection Fine crustal structure of earthquake region |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《地球物理学报》浏览原始摘要信息 |
| 点击此处可从《地球物理学报》下载免费的PDF全文 |
