台差法提高低信噪比下走时变化探测精度的研究

摘要

为研究噪音对主动源信号走时变化提取精度的影响,采用对比数值实验的方法.按照常规流程,首先用反褶积去除震源激发时间的不确定性干扰,压缩子波以得到更加尖锐的震相,由于发现反褶积会降低信号的信噪比,于是提出了台差法来代替反褶积矫正气枪激发的不确定性,再结合干涉法提取走时变化,并定量对比了两者的走时变化提取精度,最后尝试用台差法提取主动源走时的日变化.结果表明,台差法可以有效矫正震源激发时刻的影响,且不降低信噪比,从而也能获得较高走时变化提取的精度.%We adapt numerical tests to study the influence of noises on the precision of travel time drift of active source signals.In traditional ways,deconvolution is used to eliminate the uncertainty of the excitation time of active source.However,this process will significantly lower the signal-noise ratio and thus lead the decline of precision.We put forward a new method named pair difference to replace deconvolution for the sake of eliminating the influence of the active source.The results show that pair difference can effectively eliminate the impact of active source and will not affect the signal-noise ratio,thus improving the precision of extracting travel time drifts.