AMPLIFICATION PATTERN OF 2D SEMI-ELLIPTICAL SHAPED VALLEYS SUBJECTED TO VERTICALLY PROPAGATING INCIDENT WAVES

This paper presents the preliminary results of an extensive numerical parametric study on seismic behavior of two-dimensional semi-elliptical shaped valleys subjected to vertically propagating incident P and SV waves. The medium is assumed to have a linear elastic constitutive behavior. All calculations are executed in time-domain using the direct boundary element method. Clear perspectives of the amplification patterns are presented by investigation of the frequency-domain responses. It is shown that site geometry, wave characteristics and material parameters, which have been listed in decreasing order of importance, are the key parameters governing the valley's amplification pattern. It is also shown that the seismic motion would be amplified at the edge and out of the valley and de-amplified inside the valley considerably, which could result in important relative displacements along line structures founded across the valley.