Comparison of linear and non-linear seismic response of 2-dimensional alluvial basins

Abstract

Both geological and topographical conditions are known to strongly influence the nature of ground motion at a site. In particular, soft sediment filled basins may cause significant amplification of earthquake motions due to wave phenomena such as focusing and resonance.

As two-dimensional nonlinear analyses of ground response using models designed for yielding structures are beginning to find their way into soil engineering practice, our purpose in this paper is to investigate the similarities and differences of the responses computed with one of these methods and with a linear method for a prescribed 2-D problem.  

We chose a sediment filled valley and used a recorded earthquake to generate two amplitude input levels. The nonlinear and linear computations were performed independently by two teams among the authors, upon agreement of the problem specification and parameters. To some extent our objective is also to meet the seismological and engineering viewing of this classical problem.