Seismic ground motion in a layered half-space due to a Haskell-type source. II: Applications

Abstract

In this paper, the displacement field at the free surface of a layered half-space due to a seismic source described by Haskell's model is synthesized for a representative seismic event caused by the rupture of the New Madrid fault. The displacement field is first calculated over a large area on the free surface, so that the spatial variability of ground motion can be readily determined. The displacement field is calculated both in the near-field and in the far-field, providing a complete description of ground motion by accounting for all types of waves. The extent and magnitude of permanent ground deformation is also estimated. In addition, displacement time histories are computed at selected points, with a drastically smaller memory requirement. Then, considering seismic ground motion to be a stationary and homogeneous stochastic wave, its frequency-wave number ( F− K) spectra and coherence function are calculated. It is demonstrated that the F− K spectra contain complete information describing the correlational characteristics of ground motion in both space and time.