Yellowstone Rocking

The University of Utah Seismograph Stations reports that as of 1800 MST on 2 January 2009, seismicity of the ongoing Yellowstone earthquake swarm continues. Over 500 earthquakes, as large as M 3.9, have been recorded by an automated earthquake system since the inception of this unusual earthquake sequence that began Dec. 27, 2008. More than 300 of these events have been reviewed and evaluated by seismic analysts. Depths of the earthquakes range from ~ 1km to around 10 km. We note that the earthquakes extend northward from central Yellowstone Lake for ~10 km toward the Fishing Bridge area, with a migration of recent earthquakes toward the north. Some of the dozen M3+ earthquakes were felt in the Lake, Grant Village and Old Faithful areas. Personnel of the Yellowstone Volcano Observatory continue to evaluate this earthquake sequence and will provide information to the NPS, USGS and the public as it evolves.