Gallatin County Emergency Management

Current Information

Earthquake swarms are common in Yellowstone

The University of Utah Seismograph Stations (UUSS) is monitoring an earthquake swarm which is currently active on the western edge of Yellowstone National Park. The swarm began on June 12th, 2017 and, as of 13:30 MDT on June 19th, 2017, is composed of 464 events with the largest magnitude of ML 4.4 (MW 4.4) (Figure 1). The swarm consists of one earthquake in the magnitude 4 range, 5 earthquakes in the magnitude 3 range, 57 earthquakes in the magnitude 2 range, 238 earthquakes in the magnitude 1 range, 157 earthquakes in the magnitude 0 range, and 6 earthquakes with magnitudes of less than zero. These events have depths from ~0.0 km to ~14.5 km, relative to sea level. At the time of this report, there were 115 felt reports for the M4.4 event that occurred on June 16, 2017 at 00:48:46.94 UTC (June 15, 2017 at 18:48:46.94 MDT). The M4.4 event has an oblique strike-slip moment tensor solution (Figures 1 & 2).

Earthquake swarms are common in Yellowstone and, on average, comprise about 50% of the total seismicity in the Yellowstone region.

Related figures can be viewed on the original post: http://quake.utah.edu/research/special-events/ongoing-yellowstone-earthquake-swarm-north-of-west-yellowstone-mt

This is the highest number of earthquakes at Yellowstone within a single week in the past five years, but is fewer than weekly counts during similar earthquakes swarms in 2002, 2004, 2008 and 2010.

The Yellowstone Volcano Observatory (YVO) provides long-term monitoring of volcanic and earthquake activity 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.

YVO Member agencies: USGS, Yellowstone National Park, University of Utah, University of Wyoming, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey

YELLOWSTONE VOLCANO OBSERVATORY INFORMATION STATEMENT

U.S. Geological Survey

Thursday, June 15, 2017, 9:03 PM MDT (Friday, June 16, 2017, 03:03 UTC)

YELLOWSTONE VOLCANO (VNUM #325010)

44°25’48” N 110°40’12” W, Summit Elevation 9203 ft (2805 m)

Current Volcano Alert Level: NORMAL

Current Aviation Color Code: GREEN

The University of Utah, a YVO member agency, sent out the following press release about a magnitude 4.5 earthquake near West Yellowstone, MT that occurred at 6:48 PM MDT.

PRESS RELEASE

University of Utah Seismograph Stations

Released: June 15, 2017 07:55 PM MDT

The University of Utah Seismograph Stations reports that a light earthquake of magnitude 4.5 occurred at 06:48 PM on June 15, 2017 (MDT). The epicenter of the shock was located in Yellowstone National Park, eight miles north-northeast of the town of West Yellowstone, Montana. The earthquake was reported felt in the towns of West Yellowstone and Gardiner, Montana, in Yellowstone National Park, and elsewhere in the surrounding region. Today’s earthquake is part of an energetic sequence of earthquakes in the same area that began on June 12. This sequence has included approximately thirty earthquakes of magnitude 2 and larger and four earthquakes of magnitude 3 and larger, including today’s magnitude 4.5 event. Today’s earthquake is the largest earthquake to occur in Yellowstone National Park since March 30, 2014, when a magnitude 4.8 event occurred 18 miles to the east, near Norris Geyser Basin.

Anyone who felt the earthquake is encouraged to fill out a survey form either on the Seismograph Stations website: www.quake.utah.edu or the US Geological Survey website: earthquake.usgs.gov.