Proceedings of the International Union of Geodesy And Geophysics Korea Journal of Geophysical Research Conference (IUGG한국위원회:학술대회논문집)
- 2003.05a
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- Pages.18-18
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- 2003
3D Simulation of Earthquake Ground Motion Using Locally Variable Time-Step Finite-Difference Method
- Kang, Tae-Seob (School of Earth and Environmental Sciences Seoul National University) ;
- Baag, Chang-Eob (School of Earth and Environmental Sciences Seoul National University)
- Published : 2003.05.01
Abstract
Three-dimensional finite-difference simulation of earthquake ground motion is performed using a locally variable time-step (LVTS) scheme matching with discontinuous grids. Discontinuous grids in three directions and extension of the discontinuous grids' boundary to the free-surface in the LVTS scheme minimize the cost of both the computational memory and the CPU time for models like the localized sedimentary basin. A simplified model of sedimentary basin is dealt to show the feasibility and efficiency of the LVTS scheme. The basin parameters are examined to understand the main characteristics on ground-motion response in the basin. The results show that the seismic energy is concentrated on a marginal area of the basin far from the source. This focusing effect is mainly due to the constructive interference of the direct S-wave with the basin-edge induced surface waves. The ground-motion amplification over the deepest part of the basin is relatively lower than that above the shallow basin edge. Therefore the ground-motion amplification may be more related to the source azimuth or the direction of the incident waves into the basin rather than the depth of it.
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