Seismic Aggravation in Shallow Basins in Addition to One-dimensional Site Amplification

Abstract

We first classify various basin effects, as the result of sequential combinations of basic wave phenomena, into wedge effects, lens effects, and surface-wave related effects. We then investigate their contributions to the basin aggravation. Our results show that, in a shallow basin, current 1D-based approaches to assess site effects can significantly underestimate the seismic hazard in its close-to-edge region inside the basin at spectral periods below the fundamental period of the soil column at the deepest portion of the basin. In contrast, for a deep basin, ground motions across the whole-width could be underestimated using 1D approaches.