High-resolution Rayleigh wave phase velocity maps from ambient noise tomography in North China

作     者：Jiatie Pan Institute of Geophysics, China Earthquake Administration, Beijing 100081, China 

作者机构：1. Institute of Geophysics China Earthquake Administration Beijing 100081 China 

出 版 物：《Earthquake Science》 (地震学报（英文版）)

年 卷 期：2012年第25卷第3期

页      面：241-251页

核心收录：

学科分类：081801[工学-矿产普查与勘探] 081802[工学-地球探测与信息技术] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the National Natural Science Foundation of China(No.41104029) National Nonprofit Institute Research Grant of Institute of Geophysics, China Earthquake Administration (No.DQJB11B04) Basic Research Project of Ministry of Science and Technology China(No.2006FY110100) 

主　　题：Rayleigh wave phase velocity ambient noise tomography wavelet transformation North China Craton 

摘      要：We presented high-resolution Rayleigh wave phase velocity maps at periods ranging from 5 s to 30 s in the northeast part of the North China Craton (NNCC). Continuous time-series of vertical component between October 2006 and December 2008, recorded by 187 broadband stations temporarily deployed in the NNCC region, have been cross-correlated to obtain estimated fundamental mode Rayleigh wave Green’s functions. Using the frequency and time analysis technique based on continuous wavelet transformation, we measured 3 667 Rayleigh wave phase velocity dispersion curves. High-resolution phase velocity maps at periods of 5, 10, 20 and 30 s were reconstructed with grid size 0.25°× 0.25°, which reveal lateral heterogeneity of shear wave structure in the crust and upper mantle of NNCC. For periods shorter than 10 s, the phase velocity variations are well correlated with the principal geological units in the NNCC, with low-speed anomalies corresponding to the major sedimentary basins and high-speed anomalies coinciding with the main mountain ranges. Within the period range from 20 s to 30 s, high phase velocity observed in eastern NCC is coincident with the thin crust, whereas low phase velocities imaged in central NCC is correlated to the thick crust. However, the low-velocity anomaly in the Beijing-Tianjin-Tangshan region displayed in the 20 s and 30 s phase maps may be associated with fluids.