Limitations of the Vs30 parameter for the prediction of strong motion

Abstract

The Vs30 parameter, that is, the harmonic average of the S waves in the first 30 meters of the surface, has been
extensively used to model the local conditions of a site. However, several studies have shown the deficiencies
that this parameter has to effectively predict the strong movement. In the present study, non-ergodic seismic
hazard estimates are compared with the same ones made considering Vs30 to show their limitations. It is
observed that, in general, for hard soils, the estimates are similar, but for soft soils, great differences are
observed. This is accentuated for soils with periods over 1 s, considering long response periods. These
results reflect that the parameter Vs30 does not manage to capture in a good way the behavior of soils with long periods.