Combination Approach of Analogue Geological Modeling and Computational Seismic Modeling for Seismic Exploration

The aim of this study is to make data base of interpretation templates which improve accuracy of the seismic interpretation by synthesizing the seismic responses based on the complex geologic structure reproduced by analogue modeling. We combine "analogue geological modeling" and "numerical seismic modeling" to make clear the seismic responses for complex geological structures. In the analogue geological modeling, the thrust structures in the accretionary prism are reproduced under compressive stress field by using granular materials (dry sand and grass beads), a vinyl sheet, and a fixed wall. For the two-dimensional thrust structure, a fixed wall is set vertical to the direction of shortening, and for the three-dimensional structure the fixed wall is set obliquely to the shortening direction. We observe the formation process and of the thrust structures. Then we build 2D and 3D numerical structure models with velocity for the seismic modeling by interpretation of the geological boundaries on the sections of reproduced structure by the analogue experiment. We carried out the seismic modeling with based on the structure model with a finite difference method for wave simulation and we obtain synthetic seismic data corresponding to the shot record and the CMP stacked data in the seismic exploration. It was confirmed complex wavefields in the synthetic seismic sections by the influence of the complicated thrust structures. We process the synthetic data with the depth migration and image the thrust structure in the depth sections. The feature of synthetic seismic sections and the migrated sections are common to the actual field record by reflection seismology in Nankai Trough. These results show the validity of the analogue model experiment and the construction data base of the template by combining the analogue modeling and the numerical wave simulation.