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A New Scalar Imaging Condition for Vector-based Elastic Reverse Time Migration
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
Scalar images (i.e. PP-, PS-, SP- and SS-wave images) of elastic reverse time migration (RTM) can generated by applying an imaging condition to pure wave modes. Decoupled P- and S-wave equation provides an alternative way to separate P- and S-wavefields in elastic RTM. However, the output separated wavefields are both vectorial. To obtain the scalar images, we propose a new imaging condition in which the scalar product of two vector wavefields is exploited to produce scalar images in elastic RTM. For this scalar-product-based source-normalized elastic crosscorrelation condition needs, no additional prior information is required, except for the P- and S-wave velocities. And additional polarity reversal correction methods are not required to correct polarity changes in converted-wave images for the output separated wavefields have consistent amplitude polarity. Numerical example on Marmosui2 is used to test the effectiveness and robustness of our new imaging condition.