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Efficient Near Surface Waveform Tomography in Irregular Topography based on Body-fitted Grid
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 74th EAGE Conference and Exhibition incorporating EUROPEC 2012, Jun 2012, cp-293-00731
- ISBN: 978-90-73834-27-9
Abstract
Seismic waveform tomography with irregular topography surface is efficiently and stably implemented by finite difference method, based on body-fitted grid with PML boundary condition. The body-fitted grid can well coincide with the irregular surface. It is smooth and orthogonal enough to guarantee the implementation of waveform tomography. When generating body fitted-mash, boundary modification is applied to both the four model boundaries and the surface which is the internal grids within the numerical model. It can dramatically improve the orthogonality of the all grids. Both the acoustic wave equation and PML boundary condition have also been extended to the computational space coordinate for irregular topography surface waveform tomography. Synthetic example demonstrates the potential of the inversion in idealized circumstances. The spatial structures under the earth, such as thin high velocity layer, low velocity structure with irregular inverted triangle form, and keen-edge structure, have been well recovered in the reconstructed velocity model.