"The current number of daily earthquakes is well above typical daily earthquake activity at Yellowstone. Nevertheless swarms are common at Yellowstone, with magnitudes occasionally above 4.0."<p>"At this time, there is no reason to believe that magma has risen to a shallow level within the crust or that a volcanic eruption is likely. The current swarm earthquakes are likely the result of slip on pre-existing faults rather than underground movement of magma."<p><a href="http://www.seis.utah.edu/req2webdir/recenteqs/Maps/Yellowstone.html" rel="nofollow">http://www.seis.utah.edu/req2webdir/recenteqs/Maps/Yellowsto...</a>
<a href="http://volcanoes.usgs.gov/yvo/" rel="nofollow">http://volcanoes.usgs.gov/yvo/</a>
<a href="http://volcanoes.usgs.gov/yvo/publications/2010/10swarm.php" rel="nofollow">http://volcanoes.usgs.gov/yvo/publications/2010/10swarm.php</a>