I have been watching Yellowstone off an on for years. In the last 2 years, Yellowstone has been behaving oddly (Well.. Yellowstone has always been a bit odd... perhaps odder?). There was a pretty major swarm of earthquakes near one of the domes about 2 years ago, and they were fairly energetic. 24 months later (this year), Yellowstone had another large swarm. And I was just looking at the seismograph, and Yellowstone has quite a few strong earthquakes again in a possible new swarm: http://www.quake.utah.edu/req2webdir/recenteqs/Maps/111-45.html Anyone know the cause? Hydrothermal maybe?