These asperities, seem, as John and Chris have said, to increase stress as the areas around them release stress. (If I'm reading them right.)

Don, the one mountain example you forgot to mention is "going under the mountain," as opposed to your examples of going around or over. This seemed to happen in the Loma Prieta EQ, in which much of the damage occured in the Marina District of SF and in Oakland.

In such a case, the energy seemed to flow beneath the intervening "mountain," bounce off the mantle, and re-emerge to exact damage 90 miles to the north of the hypocenter.

Does this make sense in terms of your model?

Just another "lurker" with a question. (Sorry Canie--I'm sure you must have been preoccupied with your cat show when you wrote that.)

Cathryn