- Contents
- The problem
- Transformational and distributed volume changes
- Definition of source and moment
- Isolated bodies
- Crack-equivalent sources
- Spherical sources
- Prolate sources
- The volume displacement through spherical surfaces
- Source volume and moment
- A mathematical source model
- Acknowledgment
- References
- Appendix

A nonzero isotropic moment of a seismic source does not
by itself indicate a change of volume, nor does its absence
indicate a constant volume. Any isotropic moment may be associated
with any positive or negative volume change. A relationship between
the isotropic moment and the volume change can only be established
when the geometric boundary of the source is precisely defined.
A definite and general relationship exists however between the
isotropic moment and the volume displaced through any spherical
surface enclosing the source.

2003-05-30