Hi Don:

Maybe the logic behind "the Bay Area can expect at least a 7.0 magnitude quake in the next 30 years" is flawed (despite a good effort and intentions). Maybe the process is random and you could get 2 M7's in a row in the same week or none for 10,000 years.

True enough in general in the M7 to M4 comparison with the point that earth resonances might channel more M4 energy into more building trashing frequency bins on occasion (whereas the M7 {say out in the desert} may not.... So, like real estate, location is everything. Your point is well regarded though...32768 is a big factor.

As an aside, Maybe the "stress release" idea is off-target. There may be a relationship involving prior earthquakes in a given area (as an indication of a strong future quake) but the standard rationale for it (stress build-up and release) is incorrect.

What if you were forced to completely abandon "stress build-up and release" as a paradigm in "understanding" earthquakes. Where else might one look for another explanation ?

What if to "make a quake" you need A + B (to make Q = quake). What if "B" has to do with location...a property of the location.

Back to your point...yes, in the paradigm of stress release, all those little popcorn quakes do not make a feasible "stress releasing" stream (to follow that line of thought).

Just thinking aloud with my $.02 worth....