Some earthquake statistics and graphs

I'm going through some browser bookmarks and saving them to my Delicious lists, and listing some here as I go.

There are some nice data sets and some linked  visualizations of earthquake statistics on this page from the U.S. Geological Survey.  As copied in the table below (click on it for a larger version), Note that the number of quakes above magnitude 6 have not increased over time.  There is an apparent increase in the number of smaller earthquakes, but this is an artifact of better seismograph networks.