Application of Time-window Selection Method in Tomography with Topographic Effects

Abstract:

After the Wenchuan earthquake, Longmen Shan near surface structure and its association with the Wenchuan earthquake has become a very important scientific problem in the study of structural geology. However, the existing modes of Longmen Shan near surface structure could not explain the surface structural deformation and the deep structure data well. We use finite-difference method to image the Longmen Shan near surface structure. Zhang and Chen(2006,2012) proposed the MacCormack high order non-staggered finite difference method based on curved grids to precisely solve irregular surface problem. We use the method to simulate seismic wave propagation in the presence of surface topography. This article mainly focus on the window selection problem in finite-frequency tomography, using automated window selection algorithm to replace handpicking seismic phase. Then we demonstrate the advantage of our method by comparing with handpicking seismic phase. The results confirm the time-window selection method can deal with large amounts of data effectively.