جداسازي امواج بالارونده و پايين رونده در داده هاي پروفيل لرزه اي قايم با استفاده از تجزيه مقدار تكين

Separation of downgoing and upcoming waves in vertical seismic profile data using singular value decomposition.

Upcoming and downgoing wave separation is very important in VSP data interpretation. In this paper, we utilized the eigenimage idea of SVD method to separate upcoming and downgoing waves. This method is applied to synthetic and real data and the results are compared with that of the f-k method. The two dimensional Fourier method in order to be applied to separation of two types of waves requires a uniform sampling both in time and space. In addition, using a median filter for these purposes requires the seismic event to be aligned perfectly. According to the results of this study from the application of the two methods to synthetic and real data, the SVD method is preferred because there is no need for uniform sampling or perfect alignment of the seismic events. Furthermore, the nature of the eigenimage idea causes the noises to be cancelled from data while separating the waves. All the computer codes utilized in this study were developed by the authors.