Newest Volcano Notice Including Yellowstone

Yellowstone Caldera activity remains at background levels, with 118 located earthquakes in June (largest = M2.4). Deformation measurements indicate no significant uplift or subsidence of the caldera or north caldera rim since January 2026.  A small hydrothermal explosion occurred in Biscuit Basin on June 13.

Recent Work and News

A small hydrothermal explosion occurred in Biscuit Basin at about 5:09 a.m. MDT on June 13.  The event took place 30–60 meters (100–200 feet) north of Black Diamond Pool and was well recorded by seismic and acoustic monitoring in the basin, and it threw rocks a few meters (tens of feet) into the air and discharged large amounts of sediment-rich hot water into the Firehole River, causing a temporary discoloration for many kilometers (miles) downstream.  The explosion opened several vent areas, some of which were full of near-boiling water when observed the following day, including a crack that was about 18 meters (60 feet) long.  A day or two after the explosion, a pool of boiling water formed by collapse.  That pool was observed to erupt like a geyser on June 18 and again on June 23.  Black Diamond Pool and other thermal features in Biscuit Basin were not impacted by the new hydrothermal activity, and Black Diamond Pool had at least two very small eruptions (about 1 meter, or 3 feet, in height) in late June.  Biscuit Basin has been closed to visitors since the July 23, 2024, hydrothermal explosion from Black Diamond Pool that destroyed a stretch of boardwalk in the basin.

Echinus Geyser, in Norris Geyser Basin, remained active, with one eruption in June.  In July, Yellowstone Volcano Observatory scientists plan to begin installation of a new monitoring station that will include seismic and infrasound sensors in Upper Geyser Basin.

Seismicity

During June 2026, the University of Utah Seismograph Stations, responsible for the operation and analysis of the Yellowstone Seismic Network, located 118 earthquakes in the Yellowstone National Park region. The largest event of the month was a microearthquake of magnitude 2.4 located about 12 miles south-southeast of Lake in Yellowstone National Park on June 7 at 5:52 a.m. MDT.

June seismicity in Yellowstone was marked by three swarms:

1. A swarm of 25 earthquakes occurred about 12 miles south-southeast of Lake in Yellowstone National Park during June 6–9. The magnitudes ranged from M0.3 to M2.4. The largest earthquake in the sequence was also the largest in June (described above).

2. A swarm of 20 earthquakes took place approximately 12 miles north-northeast of West Yellowstone, Montana, during June 22–25. The range of magnitudes was M0.2–2.1.

3. A swarm of 16 small earthquakes occurred about 10 miles north-northeast of Old Faithful in Yellowstone National Park during June 14–15 and had magnitudes spanning the range M0.5–1.6.

Earthquake activity in Yellowstone is at background levels.

Ground Deformation

Data from continuous GPS stations indicate little net deformation in the region since January 2026.  The uplift that started in July 2025 on the north caldera rim ceased by mid-January 2026, and there has been no uplift or subsidence of Yellowstone Caldera since December 2025.

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