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Alert Level: NORMAL, Color Code: GREEN
2018-09-05 02:27:05 UTC





YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Tuesday, September 4, 2018, 8:27 PM MDT (Wednesday, September 5, 2018, 02:27 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

Recent work and news

Steamboat geyser, in the Norris Geyser Basin, erupted three more times in August, on August 4, 22, and 27. Field work in the caldera area included geologic investigations to better understand the ages and characteristics of the numerous lava flows that erupted since the last caldera-forming event 631,000 years ago. In addition, the Hydrothermal Dynamics of Yellowstone Lake (HD-YLAKE; https://hdylake.org/) project, which involves a team of scientists from several institutions with major funding from the National Science Foundation, completed two weeks of field work that focused on the hydrothermal system that lies on the floor of Yellowstone Lake.

Seismicity

During August 2018, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 102 earthquakes in the Yellowstone National Park region. The largest event was a micro earthquake of magnitude 2.5 located about 13 miles north-northwest of Pahaska Tepee, WY, on August 7, at 4:19 AM MDT.

A sequence of 13 earthquakes occurred about 8 miles north of West Yellowstone, MT, on August 2-3. The largest event was a micro earthquake of magnitude 2.2.

A sequence of 14 earthquakes occurred about 4 miles north of West Thumb, WY, on August 26. The largest event was a micro earthquake of magnitude 2.0.

A sequence of 12 earthquakes occurred about 14 miles south-southeast of Mammoth Hot Springs, WY, on August 29-30. The largest event was a micro earthquake of magnitude 2.4.

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

After showing little or no change in July, surface deformation recorded by GPS stations in Yellowstone resumed the trends that have been persistent since 2015. Stations in the caldera are subsiding by a few centimeters per year, while the station near the Norris Geyser Basin returned to uplifting by a few centimeters per year. The lack of measurable surface motion in July was probably an aberration caused by seasonal changes, perhaps due to surface and subsurface water conditions.

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, 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




YELLOWSTONE VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Wednesday, August 1, 2018, 4:23 PM MDT (Wednesday, August 1, 2018, 22:23 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

Recent work and news

Steamboat geyser remained active in July, with eruptions on July 6 and 20. Some field work also took place in the Park, including geological mapping and the installation of a new gas monitoring array at Bison Flat near the Norris Geyser Basin. The gas sensors are designed to run year-round and are the first of their kind in Yellowstone. All other gas monitoring in the park consists of spot checks or temporary deployments that have never been continuous for more than a few months at a time. We are hopeful that this new data stream will provide insights into how gas concentrations vary according to seasonal (summer versus winter) and environmental (wind, rain, temperature, humidity, etc.) conditions.

Yellowstone Volcano Observatory scientists are also continuing to assist colleagues in Hawaiʻi with the response to the ongoing crisis at Kīlauea Volcano.

Seismicity

During July 2018, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 153 earthquakes in the Yellowstone National Park region. The largest event was a micro earthquake of magnitude 2.5 on July 4 at 7:09 PM (MDT) and was part of a small sequence of 12 earthquakes located about eight miles east southeast of West Thumb, WY, and that occurred during July 2–10.

A larger sequence of 77 earthquakes occurred ~14 miles south-southwest of Mammoth, WY, during July 16–27. The largest earthquake of this swarm was a micro earthquake of magnitude 2.3 on July 24 at 8:40 PM (MDT).

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

Motion at nearly all GPS stations in Yellowstone was flat throughout July. During the first half of 2018, patterns of caldera subsidence and Norris uplift were steady, following trends that had been persistent since 2015. Since late June and through July, however, there has been no significant deformation recorded in the Norris and caldera areas. Whether this is a seasonal hiccup or a longer-term change remains to be seen. Similar pauses in deformation trends have occurred during previous summers, suggesting that seasonal changes, perhaps due to surface and subsurface water conditions, play a role in controlling Yellowstone deformation.

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, 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