Michael Poland

Map of seismicity (red circles) in the Yellowstone region during 2022. 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.

Google Earth image of the north part of Lower Geyser Basin showing the site of the Fountain Hotel and nearby Leather Pool, which was tapped to provide a source of hot water for the hotel.

Interferogram created from data collected on September 29, 2021, and October 6, 2022, by the Sentinel-1 satellite system. Colored fringes indicate a change in distance (called range change) between the satellite and ground surface that is caused by surface deformation.

Looking northeast from teh Green Mountain lookout at the Springerville volcanic field in eastern Arizona.  All of the forested hills in the distance are cinder cones that mark eruptive vents of the field.  USGS photo by Mike Poland, September 22, 2022.

Front cover of the Yellowstone Volcano Observatory’s Volcano and Earthquake Monitoring Plan for the Yellowstone Caldera System, 2022–2032.

Map of SNOTEL snowpack telemetry sites (blue dots) and streamgages (red dots) in and around Yellowstone National Park.

Yellowstone River level (left) and discharge (right) during June 9–16, 2022, measured at the Corwin Springs streamgage just north of Yellowstone National Park (https://waterdata.usgs.gov/mt/nwis/uv/?site_no=06191500&PARAmeter_cd=00065,00060,00010).  The

Panoramic image of the Sulphur Springs thermal area in Valles Caldera, New Mexico.  The altered surface, composed of clays, strongly resembles acid-sulfate thermal areas in Yellowstone National Park, like the Mud Volcano region.  USGS photo by Mike Poland, June 10, 2022.

Panoramic image of Valles Caldera, New Mexico, looking at the Valle Grande, part of the calderas “moat.”  The resurgent dome is the high topography at the left side of the image, while the hills at the center and right are lava domes.  USGS photo by Mike Poland, June 10, 2022.

The Bandelier Tuff near Los Alamos, New Mexico.  The Jemez Mountains, home to the Valles and Toledo calderas where the tuff originated, rise in the distance.  The tuff was hot and thick when it was deposited by caldera-forming eruptions 1.61 and 1.25 million years ago, and so it is welded in places, forming a dense and resistant rock.  USGS photo by M

Calcite Springs thermal area in Yellowstone National Park. Calcite Springs is the white altered ground. Dark deposits (not apparent in this photo) are sometimes discharged from fumaroles and are made of either oxidized sulfur or hydrocarbons. USGS photo by Mike Poland, May 15, 2022.

Scientists install a semipermanent GPS station in Yellowstone National Park.  These stations, which are not radio-telemetered, are typically installed in May and recovered in October, when the data are downloaded and processed.  These stations help to supplement the continuous GPS network in the Yellowstone area.

Vertical deformation measured at three caldera systems: Yellowstone, Wyoming (red), Long Valley, California (green), and Campi Flegrei, Italy (blue).  Triangles show data collected by leveling, and circles by GPS.  All three calderas have gone up and down over time, but the scale of change at Campi Flegrei dwarfs that at Long Valley and Yellowstone.