基于背景噪声互相关格林函数的单台时间误差估计  

Estimation of time error for a single station based on Green's function by ambient noise cross-correlation

作　　者：王俊[1] 郑定昌[2] 詹小艳[1] 江昊琳[1] 缪发军[1] 高景春[3] 

机构地区：[1]江苏省地震局,中国南京210014 [2]云南省地震局,中国昆明650224 [3]河北省地震局,中国石家庄050021

出　　处：《地震学报》2013年第6期888-901,938,共14页Acta Seismologica Sinica

基　　金：地震行业科研专项(201008002);中国地震局测震台网青年专项(20120107);中国地震局"三结合"课题(20120901);江苏省地震局青年基金(201204)共同资助

摘　　要：从江苏省数字地震台网2011年的宽频带记录数据中,选取了不同背景噪声区域下的两组不同台间距的台站(A,B每组4个台站),两组台站的平均台间距分别为44.6和30.5km.首先,运用滑动窗互相关技术,测量出各台站对间背景噪声互相关格林函数随时间的偏移量ΔDS i-S j,然后通过奇异值分解来求解由ΔDS i-S j与系数矩阵构成的超定方程,从而计算出单个台站的时钟误差ΔSi;并引入协方差矩阵来估计不同置信水平下计算结果的误差范围.计算结果表明,除去明显的钟差误差(>3s)外,8个台站的时间误差平均均方根为0.421 5s,A与B两组台站在置信水平为95%时的时间误差范围分别为±0.454 4s和±0.428 3s;而采用HYPOSAT定位方法对2010—2011年江苏地区的地震进行定位,得到的平均走时残差约为0.386s.两者的计算精度基本相当,表明基于背景噪声互相关格林函数计算出的单台时间误差是可信的.From the broadband data recorded by the digital seismic network of Jiangsu Province in 2011, this paper selected two station groups A and B （each has four stations）. The two groups were under different ambient noise area and the average station distances were 44.6 km and 30.5 km, respectively. Firstly, by the sliding window cross correlation technique, the offsets of the Green＇s function were measured by ambient noise cross correlation between station-pairs in the year 2011. Then, the singular value decomposition was applied to solve the over-determined equation of ADs-s and the coefficient matrices, so as to calculate clock error ASi for a single station＂ And the covariance matrix was in- troduced to estimate the error range of calculation results under different confi- dence level. The results showed that ignoring the obvious clock error （ ~3 s）, the average RM$ of time errors for eight stations was about 0. 4215 s, and on the 95% confidence level, the errors ranges for the two groups of stations were ~0. 454 4 s and ~0. 428 3, respectively. The average travel time residual was about 0. 386 s by adopting HYPOSAT to locate actual earthquakes in Jiangsu region during the period of 2010--2011. Therefore, both residuals are consist- ent in accuracy, suggesting it is reliable to estimate the time error for a single station based on Green＇s function by noise cross-correlation.

关 键 词：互相关格林函数 数字地震台 时间误差 连续波形数据 

分 类 号：P315.63[天文地球—地震学]