Images

Webicorder for PNSN TDH seismometer located on the southwestern flank of Mount H

As the sun rose above Mauna Kea (background) on July 6, 1975, eruptive fissures along the Northeast Rift Zone of Mauna Loa fed voluminous ‘a‘ā lava flows that quickly moved down the north flank of the volcano. USGS photo by D. Peterson.

Schematic model showing a cross section of Old Faithful's plumbing system as determined from seismic studies. The red circles (t0-t3) show the location of the tremor source over time, and how the tremor source migrates upward prior to an Old Faithful eruption. Times between red circles are based on a 93-minute eruption interval.

Graphic shows the earthquake swarm from June-July, 2019, compared to previous swarms detected in March 2019, 2017, 2016, and in 2014. The activity is likely the result of small-scale underground movements of hydrothermal fluids or gas — a sign that Mount St. Helens remains an active volcano.

What does a hardened lava flow look like? This photograph is of the frothy top of a lava flow near the fissure 8 vent, on Kīlauea Volcano's lower East Rift Zone. The different sizes and abundance of bubbles in the surface texture create different colors of the lava, including the light brown and darker black near the boot (for scale).

Computer images showing the coastal cliff area of Mud Creek on the Big Sur coastline, central California, where on May 20, 2017 a catastrophic landslide destroyed over 400 meters of scenic California State Highway 1. These illustrations show the changes to the digital surface models of Mud Creek during the three primary phases of the landslide: (

USGS photographs taken from a contracted small airplane are used to build three-dimensional representations of the hillslopes of Big Sur, California, as shown here for the Mud Creek landslide site in 2017.  Blue symbols show the locations of individual photos obtained on the flight, and the gray area shows the hillslope landscape created from the photos using S

Native sulfur crystals precipitate at Sulphur Banks via a chemical reaction between different sulfur-bearing volcanic gases. USGS image by P. Nadeau.

HVO gas geochemists periodically collect gas samples at Sulphur Banks, near the Kīlauea Visitor Center, in Hawai‘i Volcanoes National Park. Samples are analyzed for bulk chemistry and for helium isotopes. The results are compared to previous measurements to evaluate potential changes in activity at the volcano.

An HVO geologist removes the sampling tube following the gas collection. Inserting the tube down into the degassing source limits contamination of the volcanic gas sample by atmospheric gases. USGS image by P. Nadeau.

COSMO-SkyMed (CSK) Interferogram for the period from April 6 to June 2, 2019, covering Kīlauea Volcano's summit region. Each color fringe represents 1.65 centimeters (0.65 inches) of ground displacement.

Map showing the surficial geology from this study and Baldwin and others (2016) with equivalent onshore geology (adapted from Stone and DiGiacomo-Cohen, 2009). The areal extents over which offshore subsurface geologic units crop out at the sea floor were interpreted from seismic-reflection data.

Montana State University students at an outcrop along Highway 20, in Idaho, sampling the Mesa Falls Tuff fall deposit exposed just beneath the ignimbrite. Photo by Madison Myers (Montana State University) on June 9, 2019.

Magma dynamics experiments seek to recreate the pressure and temperature at depths far beneath a volcano, in order to determine how the magma forms, evolves, and ascends prior to eruption.

A debris flow in Marin County triggered by intense rainfall destroyed several homes and injured one person during February 2019.  View is looking from the top of the landslide downslope.

Areas on Kīlauea that will be covered by a helicopter lidar survey in June 2019. Red lines enclose areas over which the survey helicopter will fly at 396 m (1,300 ft) above ground level. Green lines enclose areas over which the helicopter will fly at 151 m (500 ft) above ground level. USGS map.

Map showing the three types of young faults in Yellowstone National Park. Courtesy of the Wyoming State Geological Survey.

Schematic illustration showing the inferred irregular conduit geometries of (a) Old Faithful geyser, in Yellowstone National Park; (b) Velikan geyser, in Kamchatka, Russia, with boulders at the bottom depicted in brown; and (c) Geysir, in Iceland. The walls of the conduits are lined with white silica sinter similar to that exposed on the surface.

Schematic illustration showing the inferred subsurface structure of Geyser Flat, Whakarewarewa, in the Taupo Volcanic Zone, New Zealand. From manuscript by Hurwitz and Manga (Annual Review of Earth and Planetary Sciences, 2017. Vol. 45, pp. 31–59).

USGS geologists are conducting field work at the summit today to make observations of volcanic ash and measure volcanic gas. This photograph is taken on Crater Rim Drive where the road intersects the Southwest Rift Zone. Rockfall dust and volcanic ash covers the ground and cracks in line with the Southwest Rift Zone trace traverse the pavement.

Lava on road.