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USGS Volcano Notice - DOI-USGS-YVO-2022-10-01T12:21:41-07:00

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YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Saturday, October 1, 2022, 1:33 PM MDT (Saturday, October 1, 2022, 19:33 UTC)


YELLOWSTONE (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

Recent Work and News

September field work in Yellowstone involved numerous projects, including repair and maintenance of seismic and continuous GPS stations, study of the new thermal area that has emerged in the past two decades near Tern Lake, installation of new continuous gas-monitoring equipment near Mud Volcano, geologic mapping of units associated with Yellowstone’s most recent caldera-forming eruption 631,000 years ago, a magnetotelluric study of subsurface characteristics and fluid pathways, and investigation of the causes of hydrothermal explosions in Lower Geyser Basin.  In October, YVO will close out the 2022 field season with additional field work that will include, during the first week of the month, maintenance on the Norris Geyser Basin temperature-monitoring network and the recovery of several temporary GPS stations, which are deployed every May and recovered in October before the onset of winter.

Steamboat Geyser experienced one major water eruption during the previous month, on September 18.  There have been 9 major water eruptions of the geyser in 2022.


Seismicity

During September 2022, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 678 earthquakes in the Yellowstone National Park region. The largest event of the month was a minor earthquake of magnitude 3.9 located about 14 miles south-southwest of Mammoth Hot Springs in Yellowstone National Park on September 18 at 6:55 AM MDT.  This event is part of ongoing seismicity that began in the area on July 29.  In September, 510 earthquakes were added to the sequence, and seismicity continued through the end of the month.

September seismicity was marked by three additional swarms:

1) A small swarm of 14 earthquakes, ~3 miles north-northeast of Lake Village in Yellowstone National Park, took place during September 9–10, with the largest earthquake (magnitude 2.0) occurring on September 9 at 7:52 PM MDT.

2) A small swarm of 16 earthquakes, ~11 miles south of West Thumb in Yellowstone National Park, occurred during August 31–September 1, with the largest earthquake (magnitude 3.3) on August 31 at 7:33 PM MDT (the quake occurred on September 1 at 01:33 AM in the UTC time zone and is therefore counted as a September earthquake).

3) A swarm of 34 earthquakes, ~12 miles northeast of Old Faithful in Yellowstone National Park, occurred during September 4–5, with the largest earthquake (magnitude 2.6) taking place on September 4 at 8:10 PM MDT.

Earthquake sequences like these are common and account for roughly 50% of the total seismicity in the Yellowstone region.

Yellowstone earthquake activity is currently above background levels.


Ground Deformation

Continuous GPS stations in Yellowstone Caldera and near Norris Geyser Basin recorded a transition from slight uplift to slight subsidence (0.5-1 cm, or a fraction of an inch) in mid-September.  This style of deformation occurs every summer.  The overall trend of of caldera subsidence has been ongoing since 2015, but during summer months is interrupted by a pause or slight uplift as snowmelt percolates into the ground and causes the surface to swell slightly, like a sponge.  The pause or slight uplift begins in late spring or early summer, and by late summer or early fall the deformation style returns to subsidence.  The overall rate of caldera subsidence since 2015 is a few centimeters (1–2 inches) per year.

An example of GPS data can be found at http://www.unavco.org/instrumentation/networks/status/pbo/data/NRWY (click on Static Plots / Cleaned)



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, Montana State University, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey





CONTACT INFORMATION:

Michael Poland, Scientist-in-Charge
mpoland@usgs.gov