甘孜-玉树断裂南段浅层地震反射波法探测  

Exploration for the Southern Segment of the Ganzi-Yushu Fault Zone Using Shallow Seismic Reflection Method

作　　者：赵航 李大虎[1] 赵晶[2] 张理[3] 陈学芬[1] ZHAO Hang;LI Dahu;ZHAO Jing;ZHANG Li;CHEN Xuefen(Sichuan Earthquake Agency,Sichuan Chengdu 610041;Xichang Seismie Central Station,Sichuan Xichang 615000;Kangding Seismie Central Station,Sichuan Kangding 62600)

机构地区：[1]四川省地震局,四川成都610041 [2]四川省地震局西昌地震中心站,四川西昌615000 [3]四川省地震局康定地震中心站,四川康定626001

出　　处：《四川地震》2021年第1期6-11,共6页Earthquake Research in Sichuan

基　　金：国家自然科学基金面上项目(41974066);四川省地震局地震科技创新团队项目(201804)资助

摘　　要：2010年4月14日7时49分在青海省玉树藏族自治州玉树县发生7.1级地震,地震灾区的恢复重建工作受到隐伏断裂段和余震活动等因素的严重制约,尤其是NW走向的甘孜—玉树断裂的空间展布位置对选址重建及断裂合理避让起着决定性作用。本研究以甘孜—玉树断裂南段为探测目标,在探测工作中采取了小道间距、小偏移距、多道短排列接收、共反射点多次覆盖观测的工作方式,进行跨断层的浅层地震反射波法探测,查明了甘孜—玉树断裂南段的空间展布位置和近地表构造形态,地震剖面揭示出的地层反射具有较高的信噪比和分辨率特征,且在横向上反射波同相轴可以连续追踪,地层界面的起伏变化形态和断裂构造特征也非常清楚,解译出了3支断层在覆盖层中呈花状构造展布,符合大型走滑断裂的构造样式。探测定位结果为灾后恢复重建和工程选址工作中避开断裂带、减少未来可能造成的地震灾害损失提供了科学依据。At 7:49 on April 14,2010,a 7.1 earthquake occurred in Yushu County,Yushu Tibetan Autonomous Prefecture,Qinghai Province.The restoration and reconstruction of the earthquake stricken areas are seriously re-stricted by hidden fault segments and aftershock activities.Especially,the spatial distribution of the NW trending Ganzi Y ushu fault plays a decisive role in site selection,reconstruction and reasonable fault avoidance.In this pa-per,taking the southern section of Ganzi Yushu fault as the detection target,the working methods of small track spacing,small offset,multi-channel short array receiving and common reflection point covering observation are a-dopted in the exploration work,and the spatial distribution position and near surface structural form southern seg-ment of Ganzi Yushu fault are found out.According to the seismic section,the reflection of the strata has high signal-to-noise ratio and resolution,and the reflection events can be traced continuously in the transverse direction.The undulating and changing shape of the stratum interface and the characteristics of the fault structure are very clear.It is interpreted that the three faults are distributed in the overburden in a flower like structure,which is in line with the structural style of large-scale strike slip fault.The results of detection and location provide a scientific basis for avoiding fault zone in post disaster reconstruction and engineering site selection,and reducing possible earthquake disaster losses in the future.

关 键 词：玉树7.1级地震 甘孜—玉树断裂 浅层地震反射波 活动断裂探测 

分 类 号：P315.7[天文地球—地震学]