The Swarm of Earthquakes that started December 26, 2008, beneath Yellowstone Lake in Yellowstone National Park has stopped for now. Similar large earthquake swarms have occurred in the past at Yellowstone, without triggering steam explosions or volcanic activity.
A series of more than 900 seismic events was most intense on December 27, 2008. The sequence included sixteen events of magnitude 3 to 3.9 and approximately 70 of magnitude 2 to 3 (as of Sunday afternoon, Jan. 4, 2009). Visitors and National Park Service employees in the Yellowstone Lake area reported feeling the largest of these earthquakes.
Listen to a podcast interview with Dr. Jacob Lowenstern, USGS Scientist-In-Charge at the Yellowstone Volcano Observatory, about how scientists monitor volcano and earthquake activity at: http://www.usgs.gov/corecast.
To view up-to-date volcano monitoring information at Yellowstone National Park, visit the Yellowstone Volcano Observatory Web site.