Could be wrong, but I think statistically, there are more quakes in the full moon/new moon window (not just one day but 3 days either side w/ the full/new moon day being in the middle)- having to do with tides and gravitational forces.
I love your screename, by the way! :)
Statistically there's no increase in quakes around full or new moons:
http://seismo.berkeley.edu/seismo/faq/planets.html
There are some slight statistical increases with certain kinds of quakes relating to DAILY tides, but not to moon phases.
However there is an OVERWHELMING desire of people to believe such a moon phase relationship exists, for reasons that are somewhat obscure to me.
A major driver of the myth is noted seismological fraud/liar Jim Berkland, a regular guest on Coast-to-Coast, though.