One interesting pattern which has surprised statisticians investigating periodicities in earthquake occurrence is that
there is a strong statistical significance for earthquakes
to occur exactly one year apart in the same region. This has
not yet been explained, but shows up over and over in statistical
studies. I cannot cite any studies at this time since I am
not in access to my office or desk, but will attempt to give
some references later to interested parties.
I was reminded of this today when a Ms 6.3 occurred in Mindanao,
Philippines which was given the following paramters by NEIS:

2002/01/01 11:29:22 6.29N 125.56E 136.5 MS 6.3 MINDANAO, PHILIPPINES

A similar, but larger earthquake occurred on Jan 1, 2001
with the following parameters:

2001/01/01 06:57:04 6.89N 126.68E 136.5 MS 7.5 MINDANAO, PHILIPPINES

By the way, Happy New Year to all.