ONE- VS TWO- OR THREE-DIMENSIONAL EFFECTS IN SEDIMENTARY VALLEYS

This study of the effects of local geological conditions on seismic ground motion uses 1D amplification as a reference point and examines, via simple theoretical and more realistic numerical examples and observations, how 2D and 3D conditions differ from 1D estimations. Because 1D simulations cannot model basin and edge effects, 1D response tends, in general, to exhibit lower peaks and be of shorter duration than 2D and 3D results. On the other hand, due to destructive interference of different types of waves, there are sites where the response can be much smaller than predicted by 1D models.