S-wave velocity structure in Tangshan earthquake region and its adjacent areas from joint inversion of receiver functions and surface wave dispersion
S-wave velocity structure in Tangshan earthquake region and its adjacent areas from joint inversion of receiver functions and surface wave dispersion
复制标题
接收函数与面波频散联合反演唐山震区及邻区横波速度结构
DOI：
10.29382/eqs-2020-0042-05
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
Zhanyong Gao
中科院分区：
文献类型：
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作者：
Yanna Zhao;Yonghong Duan;Zhuoxin Yang;Zhanyong Gao
利用唐山地震区及邻区（39°N~41.5°N，115.5°E~119.5°E）部署的83个临时和17个永久宽带地震台站的地震记录，进行了接收函数和面波频散的非线性联合反演。我们获得了唐山地震区及邻区的一些详细信息，包括沉积厚度、莫霍面深度、地壳和上地幔横波速度等。同时，我们还获得了唐山地区两个断面的vP/vS结构。结果表明：（1）莫霍面深度为30~38 km，从燕山隆起区向华北盆地逐渐变浅； (2)沉积层厚度0~3 km,自燕山隆起区向华北盆地增厚; (3)横波速度结构表明上地壳速度分布与地表地质结构具有明显的相关性,而中、下地壳速度特征与上地壳相反。与上地壳相比，中下地壳的非均质性更加明显； (4)唐山断裂两侧莫霍面的不连续性表明唐山断裂切割了整个地壳,唐山地震区下方的低vS和高vP/vS可能反映了地幔热物质通过唐山断裂的侵入。
Using the seismic records of 83 temporary and 17 permanent broadband seismic stations deployed in Tangshan earthquake region and its adjacent areas (39°N–41.5°N, 115.5°E–119.5°E), we conducted a nonlinear joint inversion of receiver functions and surface wave dispersion. We obtained some detailed information about the Tangshan earthquake region and its adjacent areas, including sedimentary thickness, Moho depth, and crustal and upper mantle S-wave velocity. Meanwhile, we also obtained the vP/vS structure along two sections across the Tangshan region. The results show that: (1) the Moho depth ranges from 30 km to 38 km, and it becomes shallower from Yanshan uplift area to North China basin; (2) the thickness of sedimentary layer ranges from 0 km to 3 km, and it thickens from Yanshan uplift region to North China basin; (3) the S-wave velocity structure shows that the velocity distribution of the upper crust has obvious correlation with the surface geological structure, while the velocity characteristics of the middle and lower crust are opposite to that of the upper crust. Compared with the upper crust, the heterogeneity of the middle and lower crust is more obvious; (4) the discontinuity of Moho on the two sides of Tangshan fault suggests that Tangshan fault cut the whole crust, and the low vS and high vP/vS beneath the Tangshan earthquake region may reflect the invasion of mantle thermal material through Tangshan fault.