Wave refocusing for linear diffractor using the time-reversal principle
S. Keydar and E. Landa
Journal name: Geophysical Prospecting
Issue: Vol 67, No 5, June 2019 pp. 1345 - 1353
Info: Article, PDF ( 5.08Mb )
One of the problems encountered in a variety of near-surface investigations is de-tecting and mapping localized heterogeneities. The heterogeneities may be classified under two kinds of objects: (1) a point diffractor that can be considered as an approx-imation of a small quasi-isometric, such as small karstic cavities and caves; (2) a linear diffractor roughly approximating an elongated object, such as a tube or fault plane. The point and linear diffractors generate two types of seismic diffraction: tip and edge waves, respectively. During the last few decades, different methods were proposed by many researchers for detecting these heterogeneities utilizing seismic waves diffracted by them. An alternative method for detecting point diffractors using a time-reversal principle combined with focusing analysis is proposed in this study: we present an extension of the time-reversal method for linear diffractors. It consists of a coherent summation of seismic energy along edge-diffraction traveltimes. Real data examples show the feasibility and efficiency of the proposed method.