Michael Poland

View looking northwest at a new thermal pool in the Porcelain Basin area of Norris Geyser Basin, Yellowstone National Park, that probably formed in a series of mildly explosive events between late December 2024 and early February 2025.  The rocks and white material (silica mud) surrounding the pool were probably ejected as the feature formed.  The pool is

Map of seismicity (red circles) in the Yellowstone region during 2024. Gray lines are roads, black dashed line shows the caldera boundary, Yellowstone National Park is outlined by black dot-dashed line, and gray dashed lines denote state boundaries.

Organization chart giving the structure of a response by the Yellowstone Volcano Observatory to a significant episode of unrest or eruption at the Yellowstone volcanic system. The strategy is scalable (elements are activated as they are needed and deactivated when they are no longer needed) and can be adapted to meet the needs of the event response.

Benchmark C9, installed by the US Coast and Geodetic Survey (now the National Geodetic Survey) in 1923 near Apollinaris Spring in Yellowstone National Park.  The number stamped into the mark, “7337.580,” is the elevation in feet that was determined by surveys the year the benchmark was established.  USGS photo by Michael Poland, September 4, 2024.

Photo of dead trees along the edge of Nuphar Lake.  The white staining at the base of the trees is a telltale sign that the trees were immersed in thermal water containing silica.  USGS photo by Mike Poland, September 1, 2024.

New steam vent at the base of a hill north of Nymph Lake, west of the highway and between Norris Geyser Basin and Roaring Mountain. USGS photo by Mike Poland, September 1, 2024.

Looking south from near a pullout along the Mammoth to Norris road just north of the Nymph Lake overlook. On the other side of the marsh is a tree-covered rhyolite lava flow, and at the base of the flow is a new thermal feature marked by a plume of steam and that formed in early August 2024.   Photo by Mike Poland, USGS, September 1, 2024.

Gibbon River near Norris Geyser Basin in Yellowstone National Park at sunset.  USGS Photo by Mike Poland, August 28, 2024.

Plot of size versus annual probability for hydrothermal explosion craters in Yellowstone National Park. The line is a model based on the energy required to form a crater of a specific size, and it is fit to known hydrothermal explosion craters in Yellowstone National Park.

Aerial view of Biscuit Basin, Yellowstone National Park, showing debris deposited by the July 23, 2024, hydrothermal explosion from Black Diamond Pool.  Major features are labeled.  The main debris field (within dashed yellow line) has a gray appearance.  Photo taken by Joe Bueter, Yellowstone National Park, on July 23, 2024.