Seismic ground motion amplification in a 3D sedimentary basin: The effect of the vertical velocity gradient

Yanfang Qin, Yanbin Wang, Hiroshi Takenaka, Xianbing Zhang

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

Ground motion amplification in sedimentary basins has been observed in some moderate or large earthquakes, such as the 1994 Northridge and 1999 Chi-Chi event. Many numerical studies with simplified 2D models have shown significant effects of the vertical velocity gradient of sediment on basin amplification. However, we need to consider a more realistic 3D model and solve wave equations with 3D numerical methods in order to improve our understanding of basin amplification. In this study, we extend a 2D pseudospectral and finite difference hybrid method to a 3D case and investigate the effects of the vertical velocity gradient for a 3D basin model. Numerical simulations were performed for four basin models with increasing vertical velocity gradients on a PC cluster using 64 processors for 67 108 864 discretized grids. The results show that the vertical velocity gradient enhances basin amplification through strong secondary surface waves and basin trapped waves. The 3D geometry of the basin causes a wave-front focusing effect that contributes significantly to a localized strong amplification with the maximum peak ground velocity in the basin. The results of this study suggest that it is important to consider the detailed properties of sedimentary basins in seismic ground motion studies.

Original languageEnglish
Pages (from-to)761-772
Number of pages12
JournalJournal of Geophysics and Engineering
Volume9
Issue number6
DOIs
Publication statusPublished - Dec 1 2012
Externally publishedYes

Keywords

  • ground motion amplification
  • parallel computing
  • sedimentary basin
  • seismic wave propagation
  • velocity gradient

ASJC Scopus subject areas

  • Geophysics
  • Geology
  • Industrial and Manufacturing Engineering
  • Management, Monitoring, Policy and Law

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