I like the expression...if it happens, it must be possible....but, there is some real doubt that the FFA rings do anything...they may not happen. Recall that on these pages Roger ran all the M5+s vs angular distance...after very large quakes (I think M8+)....and there was nothing...with the possible exception of a tiny peak at 102 deg or something like that....but certainly no large effect. Because Roger did not run much smaller quakes, M3s for example, we did not really test Lowell's work...
Chris