During September 2015, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, reports that 112 earthquakes were located in the Yellowstone National Park (YNP) region. The largest event was a small earthquake of magnitude 2.2 on September 1, at 03:27 AM MDT, located about 11 miles northeast of Old Faithful, WY.
September 2015 seismicity was characterized by two separate small earthquake swarms:
1) A small series of 24 earthquakes occurred September 4. The largest swarm earthquake (magnitude 1.5) occurred September 4, 05:14 AM MDT, located 7 miles south of West Thumb, WY.
2) A small series of 22 earthquakes mostly occurred September 24 and 25th with one event on the 29th. The largest earthquake in the series (magnitude 1.6) occurred September 24, 11:14 PM MDT, located 6 miles north northeast of West Yellowstone, MT.
Yellowstone earthquake activity in September remains at low background levels.
GPS stations in Yellowstone continue to show little or no ground movement.
http://www.unavco.org/instrumentation/networks/status/pbo/data/HVWY (click on Static Plots / Time Series)
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.
05/10/2015. Yellowstone, États-Unis :
44°25’48 » N 110°40’12 » W,
Summit Elevation 9203 ft (2805 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Source : YVO