M1.5 recorded. Many more smaller events have been detected and will be quantified by analysts in the near future. The larger events continue to be felt in the Old Faithful area of Yellowstone National Park. Over 1800 earthquakes have now been recorded since January 17, 2010, making this swarm longer (in time) and with more earthquakes than last year's swarm beneath Yellowstone Lake (December '08/January '09). The total seismic energy released is still somewhat less. The largest recorded swarm at Yellowstone remains the Fall 1985 swarm, located in a similar location in the NW corner of the Yellowstone Caldera. At this time, YVO scientists and their collaborators have detected no anomalous ground deformation, strain, or increased thermal activity that could indicate precursory activity to phenomena such as steam explosions or volcanic eruptions. As such, the Volcanic Alert Level remains at Normal (Aviation Color Code of Green). Yellowstone Volcano Observatory scientists consider that the swarm events are likely the result of slip on pre-existing faults and are not thought to be caused by underground movement of magma. Analysis of the swarm events is an ongoing process by all YVO scientists and University of Utah Seismograph Stations (UUSS) analysts will continue to review the earthquake data. An article on the current swarm is updated daily and can be found at: http://volcanoes.usgs.gov/yvo/publications/2010/10swarm.php --- The Yellowstone Volcano Observatory (YVO) is a partnership of the U.S. Geological Survey (USGS), Yellowstone National Park, and University of Utah to strengthen the long-term monitoring of volcanic and earthquake unrest in the Yellowstone National Park region. Yellowstone is the site of the largest and most diverse collection of natural thermal features in the world and the first National Park. YVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety. CONTACT INFORMATION: Jacob Lowenstern, USGS Scientist-in-Charge, Yellowstone Volcano Observatory jlwnstrn@usgs.gov " />