祁连山中东段地区断层构造和构造变形特征研究  

Study on Fault Structure and Tectonic Deformation Characteristics of the Middle-East Section of Qilian Mountain

作　　者：周琳[1] 李长军[1] 李君 庄文泉 ZHOU Lin;LI Zhangjun;LI Jun;ZHUANG Wenquan(The Second Monitoring and Application Center,Xi’an 710054,China)

机构地区：[1]中国地震局第二监测中心,西安市710054

出　　处：《大地测量与地球动力学》2022年第6期565-568,583,共5页Journal of Geodesy and Geodynamics

基　　金：中国地震局地震科技星火计划(XH20082Y)。

摘　　要：基于中小地震重新定位结果和震源区应力场等地球物理资料,分析祁连山中东段地区断层构造和构造变形特征。结果表明:1)祁连山中东段地区震源深度主要分布于2~20 km。龙首山断裂震源深度分布呈上宽下窄的倒三角形;门源6.4级地震的余震震源深度为5~15 km,倾向SW;金强河断裂东段地震活动性强,倾向NE,倾角较高;老虎山断裂东段地震活动性强,倾向NE,深部呈近垂直产状。祁连山中东段地区震源深度自西向东递增,推测祁连山东段地区更深部可能已发生构造活动。2)研究区主压应力方向为NE-NEE向。3)沿祁连山中东段地区一系列走滑断裂与前缘逆冲断裂的组合破裂是青藏高原北东向挤出的一种重要的构造变形调节模式。We analyze the characteristics of fault structure and tectonic deformation in the middle-east section of Qilian mountain based on the relocation results of small and medium earthquakes and geophysical data of stress field.The results show that:1)The focal depth of the middle-east section of Qilian mountain is 2-20 km.The focal depth distribution of the Longshoushan fault is an inverted triangle with a wide upper and narrow lower.The aftershock depth of the Menyuan M_(S)6.4 earthquake is 5-15 km,with a tendency of SW.The eastern section of Jinqianghe fault has strong seismicity,with a tendency of NE and high dip angle.The eastern section of Laohushan fault is highly seismically active,with a tendency of NE and a near vertical occurrence in its depth.The focal depth of the middle-east section of Qilian mountain increases gradually from west to east.It is speculated that deeper tectonic activity may have occurred in the eastern Qilian mountains.2)The direction of principal compressive stress in the study area is NE-NEE.3)The combined fracture of a series of strike-slip faults and front thrust faults along the middle-east section of Qilian mountain is an important structural deformation regulation mode for the NE extrusion of the Qinghai-Tibet plateau.

关 键 词：地震重定位 构造应力场 震源机制解 祁连山中东段 

分 类 号：P315[天文地球—地震学]