Well, solar activity can effect our geomagnetic field, even disrupt it. You get some weird fields moving through large iron masses, and that can create tension and possibly motion. So there could be some connection.

But I am more inclined to think seismic events could link and chain just on their own volition. IIRC, there was something on the boobtube that showed such a connection in some cases based on an analysis of recent seismic activity along the San Andreas.