Prestack Depth Migration supported by Madagascar software - Summary of various methods through application to Sigsbee2a model -

Abstract

　Remarks related to various types of Prestack Depth Migration (PreSDM) supported by Madagascar have been pointed out and such methods have been compared through application to the synthetic Sigsbee2a model, which was simulated for complicated subsurface with dominant salt structure. Excellent software and script for PreSDM based on ray theory and wave theory with one-way approach have been published and supported by Madagascar so far. In addition to such tools, efficient script for Reverse Time Migration (RTM) based on wave theory with two-way approach created newly by CWP consortium has been used for the current evaluation. RTM has been considered and adopted as the best tool for imaging complex subsurface structure. Nevertheless, it has been recognized that clear image can be obtained by the current PreSDM based on the latest ray theory and revised wave theory with one-way approach. Regarding RTM, it has been desired that low frequency noise should be efficiently suppressed, and expensive calculation time should be significantly reduced. Smoothed correct velocity model included in Madagascar has been used in each PreSDM shown in this article.