Ongoing Yellowstone Earthquake Swarm North of West Yellowstone, MT.

August 03, 2017 UPDATE: 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 13:00 MDT on August 2nd, 2017, is composed of 1,562 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, 8 earthquakes in the magnitude 3 range, 134 earthquakes in the magnitude 2 range, 505 earthquakes in the magnitude 1 range, 879 earthquakes in the magnitude 0 range, and 35 earthquakes with magnitudes of less than zero.  These events have depths from ~0.0 km to ~14.0 km, relative to sea level.  At the time of this report, there were 125 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).  In addition, four other earthquakes in the swarm have been reported felt.

 

 

Figure 1. Location of the earthquakes that are part of the swarm as of August 3, 2017 at 01:00 PM MDT (red symbols).

 

Figure 2. Moment Tensor solution for the M4.4 event showing the fit between data (black) and synthetics (red dashed).

Moment Tensor for M 4.5

Figure 3. Animation of the June 2017 Yellowstone earthquake swarm.  Earthquakes appear as red circles as they happen, then transition to blue.  After they have occurred, they appear as black circles.  The size of the circles are proportional to the earthquakes magnitude.

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

UUSS will continue to monitor this swarm and will provide updates as necessary.

 

If you think you felt an earthquake, please fill out a felt report at: http://earthquake.usgs.gov/earthquakes/dyfi/.

Magnitude 4.0 east of Jackson, WY

us10004t1f_ciimOn February 26, 2016, an earthquake of magnitude 4.0 struck about 31 km (19 miles) east of Jackson, WY at about 5:00 PM local time.  The quake was reported felt by over 150 people in the Teton region.  There were no reports of any damage.  The earthquake occurred in the Gros Ventre range east of Grand Teton National Park near the location of previous seismic activity.  In 2010 there was a swarm of earthquakes, including a M4.8 earthquake, ~11 km (7 miles) north of this event.Fig04.1_seis_map

 

The Teton region is part of the Intermountain Seismic Belt, a region of relatively high seismicity in the Intermountain West that extends from northern Arizona to western Montana.  Most of the seismicity in the Teton region occurs east of Grand Teton National Park in the Gros Ventre range while there is very little earthquake activity on the Teton Fault.

 

 

 

 

News accounts for this event can be found at the following links:

Jackson Hole News & Guide, February 26, 2016

Casper Star Tribune, February 26, 2016

Jackson Hole News & Guide, February 27, 2016