There was a swarm of sixteen earthquakes in 24 hours this weekend (map above, updates at this link). It probably is not significant, but it is worth remembering that the Yellowstone caldera is a hotspot above a supervolcano, the eruption of which would mean theendoflifeasweknowit, at least for the United States. The Yellowstone one has erupted approximately every 600,000 years, and the last eruption was... lets see... 600,000 years ago.
Found at Reddit, where there is a discussion thread.
