I heard a talk by Nano Seeber a couple years ago at Lamont, and he said something like that 1/2 of intraplate EQs (in the U.S.?) are not only triggered, but they are triggered by man (fluid injection, quarries, etc.). I think it has become well-established that many quakes are triggered...that just means that they occur slightly earlier than they would otherwise...how can you say quakes are not triggered when P and S waves of large quakes like Landers set off quakes...like at Long Valley or Yellowstone? Chris