【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.更多还原

【Abstract】 From the broadband data recorded by the digital seismic network of Jiangsu Province in 2011,this paper selected two station groups Aand B(each has four stations).The two groups were under different ambient noise area and the average station distances were 44.6km and 30.5km,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 ofΔDS i-S j and the coefficient matrices,so as to calculate clock errorΔSi for a single station.And the covariance matrix was introduced to estimate the error range of calculation results under different confidence level.The results showed that ignoring the obvious clock error(>3s),the average RMS of time errors for eight stations was about 0.421 5s,and on the 95%confidence level,the errors ranges for the two groups of stations were±0.454 4s and ±0.428 3,respectively.The average travel time residual was about 0.386s by adopting HYPOSAT to locate actual earthquakes in Jiangsu region during the period of 2010—2011.Therefore,both residuals are consistent in accuracy,suggesting it is reliable to estimate the time error for a single station based on Green’s function by noise cross-correlation.更多还原