Numerical experiments for seismic tomography using the Singular Value Decomposition (SVD) technique

The purpose of this study is to learn how to consider setting the borehole and arrangement of the measuring instruments for seismic tomography. For this purpose we made an underground structure model of Unzen Volcano based on the results of previous studies, and simulated the seismic tomography identifying this model with the true structure because one of some plans in "Scientific drilling project at Unzen Volcano" is seismic tomography by using a borehole approaching conduit" We located sources and receivers along the borehole and at the surface, and calculated synthetic seismograms at the receiver positions by a 2-D finite difference method. We measured the first P arrival time in the synthetic seismograms, and constructed the observational equation for seismic tomography. We investigated the solution of this equation by the Singular Value Decomposition (SVD) technique. We found we can consider borehole location and arrangement of sources and receivers through such a simulation by Singular values and eigenvalue that got in this way.