利用小波变换提高地震波初至拾取的精确度

众所周知,折射静校正是中国西北地区地震资料处理中十分重要的环节,而准确地拾取初至又是折射静校正的基础.然而,这些地区的地震记录中,初至波却常常受到各种干扰的影响,使得其波形发生畸变,从而导致初至拾取不准确.文章首先分析了最常见的引起初至波难以准确拾取的情况,并提出了初至拾取预处理的方法.具体采用小波阈值去噪并结合连续小波变换的方法,恢复初至波的最大振幅波形,并突出初至波的起跳时刻,从而提高初至拾取的准确度.通过理论模型研究和实际资料试算表明,该方法具有很好的应用前景,它对于目前常用的拾取初至起跳时刻和拾取初至波最大峰值时刻的两类拾取方法,都具有非常重要的意义.

Improved accuracy of picking first arrival with wavelet transform in seismic survey

Picking first arrival is the base of refraction statics, and it is often difficult to do with many data in the northwest area of China. In this paper, the authors discuss the factors to influence the accuracy of picking first arrival. Contraposing these factors, the authors present the preprocessing method before picking first arrival. This method is based on the wavelet function and the transform scale selecting, uses the wavelet transform to eliminate noise by the threshold selecting method and the continuous wavelet transform to improve the first arrival's waveform of maximum amplitude, in the same time, stands out the break point time of first arrival in order to improve the accuracy of picking first arrival. The results of theoretic models and actual samples show that this method has a wonderful foreground in its application and is of important significance to those ways often used in picking first arrival.