Archambeau's Elastodynamical Source-Model Solution and Low-Frequency Spectral Peaks in the Far-Field Displacement Amplitude

• Published in: Geophysical Journal of the Royal Astronomical Society Vol. 44; no. 1; pp. 27 - 44
• Main Author: Snoke, J. Arthur
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-01-1976
• ISSN: 0956-540X; 0016-8009; 1365-246X
• DOI: 10.1111/j.1365-246X.1976.tb00273.x

An analysis of Archambeau's method for obtaining the elastodynamic source-model solution for an instantaneous rupture leads to the following conclusions: (1) For most problems of interest Archambeau's method of solution is not exact because it neglects dynamical boundary conditions. (2) For calculating far-field displacements, Archambeau's method of solution is equivalent to Randall's. (3) Archambeau's solution for a stress relaxation model gives a good approximation of the exact solutions for the far-field displacements. (4) Solutions obtained by Archambeau's method have been presented and interpreted as initial-value-model solutions, but they can also be represented as boundary-value-model solutions. It is apparent from the boundary-value-model representation that all discontinuity surfaces in the elastic medium radiate simultaneously, whereas in this representation only the boundary should be a source of radiation. Anomalous spectral structure in models employing Archambeau's method of solution is found to result from radiation from discontinuities other than the rupture-zone boundary and is therefore spurious.