John,
sure, hazard would go up on adjoining faults...that is not what I was talking about...I have been talking about the same part of the same fault. Actually, for subparallel strike-slip faults, hazard may drop on parts of the parallel fault, as you know (static stress butterfly pattern). As for your comment on aftershocks...stresses are redistributed so that you would expect non-parallel fault to be weakened and strengthed...so aftershocks are on those that were weakened. And, the shear stresses near the end of the ruptures should go up. And, and now I'm getting a bit out of my league...static stress changes are more or less instantaneous (?) but there is a diffusion (wrong word?) of stress change away from a rupture through time...don't know what this is...fluids? I heard it in a talk or 2 some time ago. So, aftershocks are non-surprising...again, I'm specifically talking about repeat major earthquakes. I'm not aware of them happening without time (decades) for the stress to build up. Wrightwood is considered a bit of an abberation (sp?): 1812 and maybe 1857...was tail end of 1857? Or, do I have this wrong and 1857 did not make it that far? (tree rings showed 1812....).

"Your argument is often posed as to why aftershocks should not occur - why should earthquakes occur hours to years later if the dynamic stresses were not enough to set them off? Yet epicentral regions are filled with aftershocks just seconds after the dynamic waves have dissipated."

Chris