基于背景噪声互相关函数的地震观测密集台阵时钟偏差分析方法

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

利用地震观测台阵中相邻台站间背景噪声互相关函数随时间的偏移的特性,考虑参考互相关函数、噪声源变化、反演方法和数据误差的影响,给出基于背景噪声互相关函数的密集台阵时钟偏差分析及其误差评价方法。对盐源短周期地震观测密集台阵的单台时钟偏差分析结果表明,基于背景噪声互相关函数的时钟偏差分析方法可以给出连续的单台时钟偏差,并能够筛选出有明显时钟偏差的台站及偏差出现的时段。该台阵的209个台站中,有17个台站在观测期内出现大于1 s的时钟偏差,可能与仪器数据采集装置的硬件或软件故障有关。

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.