A Synchronizing Method for Dense Seismic Array Based on Ambient Noise Correlation Function

TIAN Yuan1,2, WANG Weitao2,†, LI Li2, YU Changqing3, ZHANG Haiming4

1. China Academy of Electronics and Information Technology, Beijing 100041; 2. Institute of Geophysics, China Earthquake Administration, Beijing 100081; 3. Institute of Geology, Chinese Academy of Geological Science, Beijing 100037; 4. School of Earth and Space Sciences, Peking University, Beijing 100871; † Corresponding author, E-mail: wangwt@cea-igp.ac.cn

Abstract This paper develops a Ncf-based array synchronizing and error-estimation method employing the daily time shift of NCFS between nearby stations to estimate the stability of the timing system of a short-term but densely deployed seismic array. The error related to the reference NCF, the temporal change of ambient noise field, the data error and the optimization method in inversion are all estimated and correspondingly corrected based on the characteristics of a dense seismic array. The proposed method could effectively calculate the daily clock shift of a seismic array and pick out the time period of stations with obvious clock error. As an example, among the 209 stations of Yanyuan Seismic Array, it is found that 17 stations have obvious clock error with time shift over 1 s. These clock errors might be caused by the hardware or software problems related to the data acquisition system. Key words dense seismic array; ambient noise cross-correlation function; clock error analysis; noise source distribution

地震波形的数据质量评估是使用地震数据进行科学研究的必要前提。随着地震观测密集台阵(简称密集台阵)数据处理和应用技术(简称台阵技术)的快速发展, 已有大量密集台阵数据应用于高精度地下结构成像和地震定位等对波形记录的时间准确性

要求很高的研究中。具备准确和统一的时间轴, 是应用大规模密集台阵数据进行深度科学研究的前提之一。现今的地震仪大多使用数据采集器自动连接全球导航系统(GPS)进行授时, GPS信号断开时则使用