Far-Field Waveforms from an Arbitrarily Expanding, Transparent Spherical Cavity in a Prestressed Medium.

摘要

Stress relaxation due to a growing cavity in a uniformly prestressed (pure shear) elastic medium is investigated. A simple representation of the far-field radiation is obtained. A planar, circular dislocation of same growth history as the cavity is constructed which yields the same far-field pulses, except for geometrical effects. It is shown that different equivalent dislocations must be used to model P and S pulses wherever the rupture velocity is trans-sonic. Simple analytical forms for the far-field pulses are derived which hold even in the case of relatively complicated source growth history. The dependence of waveforms on the various source parameters is illustrated by selected waveform calculations. It is suggested that this model yields an adequate representation of the far-field tectonic release radiation from underground explosions.