you do know earthquakes are not point processes?
Posted by John Vidale on January 13, 2007 at 19:40:00:

The slip distribution in large earthquakes can be quite uneven. So it is far too soon to say the same patch slipped twice in these two earthquakes. Take a look at the variations in slip along the 2004 Sumatran earthquake or the 1906 San Francisco earthquake.

The separation between the epicenters or the centroids tells only part of the story.