Abstract: A simulation method for multi-point spatially correlated earthquake ground motions in sedimentary valleys, which considers the scattering effect of seismic waves, is proposed. Based on elastic wave propagation theory, a reasonable power spectrum, coherence function and transfer function model were used to obtain multi-point spatially correlated earthquake ground motions in sedimentary valleys using the prototype spectral representation method and then the feasibility of the method was verified. The transfer function obtained by the dynamic boundary element method can fine model the waveform conversion and focusing effect of sedimentary valleys in a very wide frequency band. The simulations for common V-shaped valleys were performed and the results show that the valley topography and loose sediments have a significant impact on the seismic wave propagation. The spatial variability of the earthquake ground motions in the valley surface is very significant. One-dimensional models can hardly consider the scattering and focusing effects of seismic waves. As a result, the peak acceleration of the ground motion within the interior of the sedimentary region will be significantly underestimated. Seismic design of large-span structures in sedimentary valleys should adopt multi-point spatially correlated earthquake ground motions input which considers the scattering effect of seismic waves.

Key words: earthquake ground motions, spatially correlated, scattering, sedimentary valleys, local site effect