利用H/V谱比法研究三河和唐山地震震区地壳浅部沉积结构  

Detecting shallow sedimentary structures in Sanhe and Tangshan seismic regions using H/V spectral ratio method

作　　者：王帅 林吉焱[1] 周铭[1] 刘巧霞[1] Wang Shuai;Lin Jiyan;Zhou Ming;Liu Qiaoxia(Geophysical Exploration Center,China Earthquake Administration,Zhengzhou 450002,China)

机构地区：[1]中国地震局地球物理勘探中心,郑州450002

出　　处：《地震学报》2023年第5期892-902,共11页Acta Seismologica Sinica

基　　金：国家重点研发计划项目(2017YFC1500204);国家自然科学基金(42004080)联合资助。

摘　　要：利用一条穿过三河和唐山地震区的密集地震探测剖面数据,采用H/V谱比法获得了三河、唐山地震区及邻近区域的地壳浅部沉积结构特征、场地共振频率及易破坏程度等参数.结果表明:研究区松散沉积层厚度约为100—800 m,呈现出NW浅而SE深的变化特征;探测剖面西北部通县隆起的沉积层厚度约为350—450 m,沉积层界面起伏平缓;大厂凹陷沉积层厚度约为300—600 m,横向变化特征显著.测线东南部唐山地震区地壳浅部存在上下两组较明显的沉积界面:上层界面深度约为100 m,呈水平展布;下层界面深度约为300—800 m,且向东南方向逐渐加深.三河和唐山地震区的场地放大系数约为3—4,场地易破坏程度均大于20,显示出地表建筑物易破坏程度较高的特征.In the Sanhe and Tangshan seismic regions and their adjacent areas,the shallow crustal sedimentary structures detecting using H/V spectral ratio method has important scientific significance for regional seismic hazard risk assessment and engineering seismic fortification.In this paper,according to the data of a dense seismic sounding profile passing through the Sanhe and Tangshan seismic regions,the characteristics of the shallow crustal sedimentary structure,the site resonance frequency and the degree of vulnerability to damage in the Sanhe and Tangshan seismic regions and adjacent areas are obtained by using the H/V spectral ratio method.The results show that the thickness of loose sediment layer in the studied area is about 100–800 m,showing the characteristics of shallow in the northwest and deep in the southeast.The sedimentary thickness of the Tongxian uplift in the northwest of the exploration profile is about 350–450 m,the sedimentary interface fluctuates gently,and the sedimentary thickness of Dachang depression is about 300–600 m,with significant lateral variation characteristics.There are two sets of obvious sedimentary interfaces in the shallow part of the Tangshan earthquake region in the southeastern part of the survey line.The depth of the upper layer interface is about 100 m and is horizontally distributed.The depth of the lower layer interface is about 300–800 m,and gradually deepens toward the southeast.The site magnification factor of the Sanhe and Tangshan earthquake regions is about 3–4,and the site's vulnerability to damage is greater than 20,showing that the surface buildings are more vulnerable to damage.

关 键 词：三河地震区 唐山地震区 短周期密集台阵 H/V谱比法 浅层沉积结构 

分 类 号：P315.2[天文地球—地震学]