Canie and Roger (and 2 cents)-Lowell used to report earthquakes that coincided with arrival of the Xrays (with occurrence of the flare). If my long-term memory serves me, Loma Prieta may have been one of these. Last fall he said a couple of small ones (less than 3) coincided. I've never looked at this myself. Might be interesting. It could be done just for California, maybe for just those times when California is sub or antisolar? By the way, if you are going to do work on this topic you should get a copy of Lowell's thesis. I sort of "dissed" something in there in a previous post, but there is lots of good stuff in there, and I know that Lowell's comps paper in about 1990 was talking about P and S wave triggering of distant earthquakes-when I'm sure most seismologists would have said "nonsense", until Landers showed it to be correct.
Lowell's thesis is from U of Colorado, 1999, Short-term variations in seismic hazard.
If enough people buy this from University microfilms, Lowell will get a small royalty (unlikely)
Chris