The response of two joined quarter spaces to SH line sources located at the material discontinuity interface

Abstract

Exact analytical solutions to problems of SH line force and line dislocation operating at the interface between two quarter spaces are derived and discussed. It is shown that the resulting fields differ from that of a homogeneous half space in the distribution of travel times, wave amplitudes and polarity of first motions. These effects are documented in the literature. It is, therefore, suggested that when constructing theoretical seismic displacement fields from source, path and site effects, it is important to use response functions that account for material heterogeneity in the source region. An extension of the formulation used in the case of SH line dislocation leads to a 3‐D representation theorem which gives the displacement field in terms of the displacement discontinuities along the rupture area. The resulting overall size scaling parameter is the ‘potency’, which does not suffer from an ambiguity associated with seismic moment in the case of heterogeneous source region. Copyright © 1989, Wiley Blackwell. All rights reserved