Earthquake source theories of Haskell, Brune, and Savage have been drawn upon to develop a description of an earthquake as a major slip accompanied by many smaller tensional and slip events. We find natural explanations of several previously unexplained observations, such as:
Robustness of the MS: mb discriminant,
P corner frequency higher than S corner frequency for shallow earthquakes,
High-frequency P/S amplitude ratio higher for shallow earthquakes than previous theories predict,
Increase of complexity as a function of third moment,
Small mb relative to MS for transform faults.
(This can also be explained by emergent short-period P wave forms or by a low-Q region underlying the source).
The theory predicts that MS:mb populations of earthquakes and explosions will not converge at small magnitudes. The theory also suggests that the standard interpretations of corner-frequency measurements can provide only a lower limit to fault-plane dimensions and, in combination with the moment, only an upper limit on stress drop.