| 华北地区地壳P波和S波速度结构的双差层析成像 |
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| 引用本文： | 马梦丹,赵爱华.华北地区地壳P波和S波速度结构的双差层析成像[J].地震学报,2021,43(1):13-33. |
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| 作者姓名： | 马梦丹 赵爱华 |
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| 作者单位： | 北京 100081 中国地震局地球物理研究所 |
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| 基金项目： | 中国地震局地球物理研究所基本科研业务费专项基金;国家自然科学基金 |
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| 摘 要： | 基于华北地区(37°N—42°N,113.5°E—118.5°E)133个固定地震台站收集到的P波和S波震相数据,利用双差层析成像法反演了该地区地壳三维速度结构并对所用地震进行了重定位.结果显示:地震走时残差均方根的平均值由重定位前的0.265 s下降至0.008 s;重定位后的震源主要分布于6—16 km深度范围内;...
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| 关 键 词： | 双差层析成像 华北地区 地壳 三维速度结构 软流圈物质上涌 |
| 收稿时间： | 2020-04-02 |
Double-difference tomography of crustal P- and S-wave velocity structures beneath North China |
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| Ma Mengdan,Zhao Aihua.Double-difference tomography of crustal P- and S-wave velocity structures beneath North China[J].Acta Seismologica Sinica,2021,43(1):13-33. |
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| Authors: | Ma Mengdan Zhao Aihua |
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| Institution: | Institute of Geophysics，China Earthquake Administration，Beijing 100081，China |
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| Abstract: | In this paper, crustal P- and S-wave velocity structures of North China （37°N?42°N, 113.5°E?118.5°E） are imaged with seismic phase data from 133 permanent seismic stations in this area by double-difference tomography, and the earthquakes used in the tomography are also relocated. The results show that the average RMS of travel time residuals decreases from 0.265 s to 0.008 s, the relocated hypocenters are mainly between 6 km and 16 km in depth, and the corresponding epicenters are mostly distributed along faults. Most of the earthquakes occur on the transitional zone between low- and high-velocity areas and on the side of the high-velocity zone. In Tangshan and Xingtai, where great earthquakes took place, low velocity bodies in middle and lower crust probably result from the upwelling of deep fluids and hot mantle material. Moreover, the velocity distribution in upper crust is very different from that in middle-lower crust. In the upper crust, it is mainly controlled by the tectonic structure and the faults; in the middle-lower crust, it is closely related to the crust-mantle interaction, the Moho uplift, and the upwelling of the asthenosphere material. Based on the tectonic pattern, evolution history and previous studies, it is deduced that the destruction of the North China Craton results in the thinning of the lithosphere and the upwelling of the asthenosphere material; hence, deep fluids and hot magma go up through faults and ruptures and intrude into the middle and lower crust; as a result, these crustal parts become weak and partly melt, which is favorable for generating earthquakes. |
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