多分量地震的时频域瞬时极化分析和滤波

Instantaneous polarization analysis and filtering for multi-component seismic signals in time-frequency domain

极化分析方法在多分量地震资料处理中起着举足轻重的作用,当波形初至很接近时,利用常规的时间域极化分析方法刻画不同波型的极化分布就变得比较困难了.基于此,在广义S变换时频方法的基础上,实现了一种时频域瞬时极化滤波方法.该方法根据多分量信号的时频谱及瞬时相位来计算瞬时极化参数(极化轴、极化率、平面化向量等).结合了时频分析方法的优势,在波形识别方面更加准确.通过极化率可以识别并分离线性极化波和椭圆及圆形极化波,通过平面化向量与各分量之间的夹角大小,定性识别平面波和非平面波.模型勘探数据及实际三分量台站地震数据处理结果表明,时频域瞬时极化滤波方法在波场分离及非平面波压制等方面具有一定的实用性.

Polarization analysis methods have pivotal role to multi-component seismic data processing. However, when several wave-type arrivals are observed at around the same time in a record,it becomes difficult to characterize the polarization attributes of the separate arrivals using methods that operate exclusively either in time domain or in frequency domain.To solve this problem,the development of techniques that simultaneously handle the time and frequency dependence of the polarization attributes is needed.A better way of including the time-frequency relationship in polarization analysis would be to use the generalization S transform（GST）.We realize a new instantaneous polarization filtering method based on the GST in time-frequency domain.The instantaneous polarization parameters（polarization axis,polarizability,planarity vector,etc.）are calculated by the time-frequency spectrum and instantaneous phase of the multi-component signals.It is more accurate in terms of waveform recognition with the advantage of timefrequency analysis. We can identify and separate linear polarized wave and elliptical or circular polarized wave,and remove plane or out-plane wave through the angle between the planarity vector and different components,followed by an inverse GST to obtain the desired wave type in the time domain.The processing results of model exploration data and real station data show that the instantaneous polarization filtering method has a certain practicality in wave field separation and out-plane wave suppression.