This reminds me of a little paperback by Gribbin & Plagemann called “The Jupiter Effect”, which I have had to resist throwing out of the window. They predicted that a particular alignment of planets would trigger a big 'quake on the San Andreas fault on 10 March 1982. I haven’t got far enough to fathom what their argument is, but see mention of Earth tides and solar winds.
I’ve just found an updated table showing the frequency of earthquakes worldwide for particular magnitude ranges:
Magnitude Average Annually
8 and higher 1
7 - 7.9 15 [just over 1 event per month]
6 - 6.9 134 [about 1 event every 3 days]
5 - 5.9 1319 [between 3 and 4 events per day]
4 - 4.9 13,000
http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php
I predict that the planet will have an event of magnitude 6.5 over the next few days. And a magnitude 5.5 somewhere tomorrow.