This site concerning
earthquake frequency has a chart of trend which suggests that there has been a steady increase of events of magnitude 7 or above from 1973 to 2006, supposedly based on data from the
USGS,
wikipedia, and
the personal website of an apparent seismology enthusiast.
There is a chart on the USGS site -
scroll down to the bottom one on this page - which shows that if all recorded quakes are included then the upward trend is less apparent.
Discerning any pattern would almost certainly generate a political and religious debate that would make the global warming kerfuffle seem like a tea party (not the political one which I would capitalize as "Tea Party", though I suspect they would vehemently take one side or the other of the issue regardless of professional bona fides or whether they had studied the facts objectively).
It would be useful to learn some
earthquake facts to better interpret what the data mean. I find numbers "12" and "13" to be particularly interesting because the total number of detectable earthquakes is only an
estimate and most of the damage is often secondary.