大三江盆地及邻区地壳结构研究  

Crustal structure in the Dasanjiang basin and its adjacent areas

作　　者：武玮洁 黄金莉[1] 李选涛 刘志坤[1] 祝淮南 Wu Weijie;Huang Jinli;Li Xuantao;Liu Zhikun;Zhu Huainan(School of Geophysics and Information Technology,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《地震学报》2022年第2期286-301,共16页Acta Seismologica Sinica

基　　金：国家重点研发计划项目(2017YFC0601406);国家自然科学基金重大研究计划项目(91114205)联合资助.

摘　　要：收集了大三江盆地及其邻区区域地震台网及多个流动台阵的连续波形及远震事件资料,采用背景噪声层析成像和接收函数叠加方法,分别获得了研究区三维S波速度结构、基底及莫霍面深度和泊松比。结果显示:浅层速度结构较好地反映了地表地形及地质特征,三江盆地呈明显的低速,虎林和勃利等小型盆地的S波速度也相对较低,而小兴安岭、张广才岭等则呈高速;到中下地壳层,盆地区则表现为明显的高速,表明到该深度层盆地已趋于稳定;依兰—伊通断裂下的低速异常延伸较深,表明它是一条较深的区域性断裂。接收函数结果显示:区内莫霍面的深度大约为30—36 km,整体较为平缓;在三江盆地内,前进坳陷的沉积层最厚,可达5.4 km,最薄处位于富锦隆起,为2.7 km,到西部绥滨断陷内沉积层又变厚,这与该盆地已知的两坳夹一隆的构造相一致。We collected continuous waveforms and teleseismic events both from the regional permanent seismic network and several temporary seismic arrays in the Dasanjiang basin and its adjacent areas and obtained the 3D S-wave velocity structure,basement depth,Moho depth and Poisson’s ratio by using the ambient noise tomography and receiver function methods.Our results show that the shallow velocity structure corresponds well to the surface topography and geological features.The Sanjiang basin shows obvious low-velocity and small basins such as Hulin and Boli basins are also imaged as relatively low velocities,while the Xiaoxing’anling and Zhangguangcailing are characterized by high velocities.In the mid-lower crust,all basins show obvious high velocities,which indicates that they are stable at this depth.The low-velocity anomaly beneath the Yilan-Yitong fault extends down to deep,indicating that it is a regional deep fault.The results of the receiver function show that the Moho depth varies gently in the range of 30 km to 36 km.In the Sanjiang basin,the sedimentary thickness beneath Qianjin depression is the thickest,which could reach 5.4 km.While the sedimentary thickness beneath Fujin uplift is the thinnest,which could be 2.7 km.Beneath the western Suibin depres-sion,sedimentary layer becomes thick again.The above features are consistent with the known tectonics of two depressions sandwiching one uplift.

关 键 词：大三江盆地及其邻区 背景噪声层析成像 接收函数 三维 S 波速度结构 改进的 H-κ 叠加方法 沉积层及地壳结构 

分 类 号：P315.2[天文地球—地震学]