Crustal thickness and Vp/Vs variation beneath continental China revealed by receiver function analysis
Crustal thickness and Vp/Vs variation beneath continental China revealed by receiver function analysis
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接收函数分析揭示中国大陆地壳厚度及Vp/Vs变化
DOI：
10.1093/gji/ggab433
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发表时间：
2021
影响因子：
2.8
通讯作者：
Lianxing Wen
中科院分区：
文献类型：
--
作者：
Shihua Cheng;Xiao Xiao;Jianping Wu;Weilai Wang;Li Sun;Xiaoxin Wang;Lianxing Wen
摘要利用中国大陆及其周边地区3837个地震台站的资料，通过对150543个接收函数的分析，建立了中国大陆地壳厚度（H）和地震纵横波速度比（Vp/Vs或κ）的高分辨率模型。将接收函数按空间分辨率划分为南北地震带和华北部分地区为0.25° × 0.25°，其他地区为0.5° × 0.5°的单元，并根据接收函数的特征进行分类，开发一种改良的H-在接收函数受沉积盆地和莫霍面结构显著影响的地区，利用κ叠加方法建立模型。地壳厚度模型显示，从羌塘地块最厚的地壳（80 km）到华夏地块南部最薄的地壳（26 km），地壳厚度有向东减薄的趋势。几个主要盆地的地壳厚度为26- 50 km，前寒武纪陆块的地壳厚度为26- 55 km。结晶地壳的Vp/Vs模型在青藏高原东南缘、腾冲火山岩区、峨眉山大火成岩省、渤海湾盆地和松辽盆地中北部、太康-合肥盆地西缘和华夏地块东南缘表现为中-高值（1.75-1.85）。华夏地块和江南造山带、鄂尔多斯地块和四川盆地的山前平原等主要地区的地壳厚度值较低（≤1.72）。讨论了中国大陆可能的构造过程、长期地壳演化和地壳成分，这些与我们推断的地壳厚度和Vp/Vs结构是一致的。该研究为地震学界未来的研究建立了地震数据共享的框架，这是发展中国地震参考模型的第一步。
SUMMARY. Using data from 3837 seismic stations deployed in or around continental China, we construct high-resolution models of crustal thickness (H) and seismic compressional and shear velocity ratio (Vp/Vs or κ) in continental China by analysis of 150 543 receiver functions. We group the receiver functions in cells with a spatial resolution of 0.25° × 0.25° in the North–South China Seismic Belt and parts of the North China Craton, and of 0.5° × 0.5° in other regions, classify the receiver functions based on their characteristics, and develop a modified H–κ stacking method to construct models in the regions where the receiver functions are significantly affected by sedimentary basins and by Moho architecture. The inferred crustal thickness model displays an eastward thinning trend from the thickest crust (80km) beneath the Qiangtang Block to the thinnest crust (26km) beneath the southern part of the Cathaysia Block. Crustal thickness is 26–50km in several major basins and 26–55km in the Precambrian cratonic blocks. The inferred Vp/Vs model in the crystalline crust displays moderate-to-high values (1.75–1.85) in the southeastern margin of the Tibetan Plateau, the Tengchong volcanic field, the Emeishan large igneous province, the north-central areas of the Bohaiwan and Songliao basins, the western margin of the Taikang Hefei Basin and the southeastern margin of the Cathaysia Block. Lower values (≤1.72) characterize the major regions of the Cathaysia Block and the Jiangnan Orogenic Belt, and the hinterlands of the Ordos Block and Sichuan Basin. We discuss possible tectonic processes, secular crustal evolution and crustal compositions that are consistent with our inferred crustal thickness and Vp/Vs structure in continental China. This study establishes a framework of seismic data sharing for future studies in the seismological community in one of the first steps of developing a China Seismological Reference Model.