January 28, 2010
Al Nash, 307-344-2015
University of Utah Seismograph Stations
Released: January 28, 2010 9:00AM MST
This release is a continuation of information updates building upon our four previous press releases on the ongoing earthquake swarm on the west side of Yellowstone National Park.
The University of Utah Seismograph Stations reports that a pair of earthquakes of magnitude 3.1 and 3.2 occurred in Yellowstone National Park. The magnitude 3.1 event occurred at 12:52 PM on January 27, 2010. The magnitude 3.2 occurred on the morning of January 28, 2010 at 1:46 AM. Both shocks were located around 9 miles to the southeast of West Yellowstone, MT and about 10 miles to the northwest of Old Faithful, WY. Both earthquakes were reported felt in Yellowstone National Park.
These earthquakes are part of an ongoing swarm in Yellowstone National Park that began January 17, 2010 (1:00 PM MST). The largest earthquake in the swarm as of 9 AM MST, January 28, 2010, has been a magnitude 3.8.
There have been 1,497 located earthquakes in the swarm of magnitude 0.4 to 3.8 up to 9AM January 28, 2010. This includes 12 events of magnitude larger than 3, with 111 events of magnitude 2 to 3, and 1,374 events of magnitude less than 2.
There have been multiple personal reports of ground shaking from observers inside the Park and in surrounding areas for some of the larger events (for felt reports, please visit http://earthquake.usgs.gov/eqcenter/dyfi/). Earthquake swarms are relatively common in Yellowstone.
Yellowstone Volcano Observatory scientists still 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.
Currently there is no indication of premonitory volcanic or hydrothermal activity, but ongoing observations and analyses will continue to evaluate these different sources.
Seismic information on the earthquake can be viewed at the University of Utah Seismograph Stations: http://www.seis.utah.edu/.
Seismograph recordings from stations of the Yellowstone seismograph network can be viewed online at: http://quake.utah.edu/helicorder/yell_webi.htm.
Anyone who has felt earthquakes in the swarm are encouraged to fill out a form on the USGS Community Felt reports web site: http://earthquake.usgs.gov/eqcenter/dyfi/.
This press release was prepared by the Yellowstone Volcano Observatory partners of the U.S. Geol. Survey, the University of Utah, and the National Park Service: http://volcanoes.usgs.gov/yvo/