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Alert Level: NORMAL, Color Code: GREEN
2019-12-02 16:59:29 UTC

U.S. Geological Survey
Monday, December 2, 2019, 9:59 AM MST (Monday, December 2, 2019, 16:59 UTC)

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

There were 3 water eruptions of Steamboat geyser during the month, on November 8, 17, and 27. This brings the total number of eruptions in 2019 to 45.

The Yellowstone Volcano Observatory is pleased to announce the publication of a new information product—an annual report! The report covers calendar year 2017, summarizing activity, including earthquakes and ground deformation, as well as efforts to monitor water and gas chemistry, growth of hot spring terraces as mapped with aerial imagery, research into hydrothermal vents at the bottom of Yellowstone Lake, investigations of past lava flow eruptions, and geyser eruptions. We are hopeful that the 2018 annual report will soon follow, and we intend to start work on summarizing 2019 activity soon after the end of the year. You can download the 2017 annual report from


During November 2019, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 107 earthquakes in the Yellowstone National Park region. The largest event was a minor earthquake of magnitude 3.1 located 19 miles northwest of West Yellowstone, MT, on November 9 at 6:28 PM MST.

The monthly seismicity in Yellowstone was capped off by the onset of a swarm of earthquakes 2 miles west-northwest of West Thumb, in Yellowstone National Park, on November 30 and continuing into December. The largest November swarm event, a minor earthquake of magnitude 2.1, occurred on November 30 at 1:14 AM (MST).

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

Yellowstone earthquake activity remains at background levels.

Ground deformation

Ground deformation in the Yellowstone area has been variable but minor over the last few months. Overall subsidence of Yellowstone caldera is indicated at stations on both the Sour Creek and Mallard Lake resurgent domes, although minor deviations are superimposed on the general trend, perhaps due to seasonal variations from inclement weather. In the area of Norris Geyser Basin, GPS data show subsidence of about 2 cm (less than 1 in) since September, but there was little net motion during the month of November.

An example of GPS data can be found at (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, UNAVCO, Inc., Wyoming State Geological Survey, Montana Bureau of Mines and Geology, Idaho Geological Survey


Michael Poland, Scientist-in-Charge