Images

A field team from the USGS Cascades Volcano Observatory discuss station maintenance plans on the north side of Mount St. Helens, Washington. Pictured in the center of the crater is a steaming lava dome from the 2004-08 eruption, and the fractured surface of Crater Glacier emerging from the gap on the north flank.  

An HVO geologist walks along the summit trail, with Mauna Kea in the background.

HVO geologists made a routine visit to the webcam monitoring Halema‘uma‘u. No changes were observed in the pit, but views were hampered by poor weather and thick fog.

HVO staff visited the summit of Mauna Loa on foot to repair the webcam. The weather was perfectly clear, and views of the caldera floor showed nothing unusual.

Serapeum, a Roman Marketplace in Pozzuoli, Italy, records deformation of Campi Flegrei caldera over two millennia. It was built above sea level about 2000 years ago, but mollusk borings on the large marble columns indicate that it subsided by 7 meters (23 feet) below sea level before being uplifted above sea level once more in the past several hundred years.

Map showing the minimum area covered by volcanic ash from eruptions of Valles Ca

HVO scientists inspect a seismic station on Mauna Loa to evaluate for a possible equipment upgrade in the near future.

Hawaiian Volcano Observatory field crews establish a new MultiGAS volcanic gas monitoring station on the south side of Kīlauea Volcano's caldera. Currently, sulfur dioxide emission rates from the summit remain low. The station will collect data to track emission rates and concentrations over time. Photo by Frank Younger.

This is a view of the summit area from the southwest, showing the collapsed area of Halema‘uma‘u and the adjacent caldera floor. A section of Crater Rim Drive preserved on a down-dropped block is visible at the far right.

HVO scientists measure a GPS instrument to ensure its stability during a multi-day deployment in the Kahuku Unit of Hawai‘i Volcanoes National Park.

Earthquakes (red dots) track the progression of the magmatic intrusion from Kīlauea Volcano's middle East Rift Zone to the lower East Rift Zone between April 30 and May 3, 2018. Orange triangles show the locations of fissure 1 (right), which erupted on May 3, and Pu‘u ‘Ō‘ō (left).

Maps displaying the stages of evolution of the more recent cycle of volcanism associated with Yellowstone Caldera. From Finn and Morgan, 2002 (High-resolution aeromagnetic mapping of volcanic terrain, Yellowstone National Park).

Color-shaded topographic relief map of the Yellowstone Plateau-Snake River Plain volcanic province showing the track of the Yellowstone hot spot. Figure by Ken Pierce and Lisa Morgan.

The sun rises at Mount St. Helens (pictured in the distance), with low-level clouds covering Coldwater Lake. The view is from the Coldwater Science and Learning Center, the site of the 2018 GeoGirls field camp program.

This thermal map was constructed by merging about 1300 images from a morning helicopter overflight, and shows the distribution of some of the prominent thermal features in the caldera. The most conspicuous area is a region of high temperatures in the deepest part of the collapse depression, in the area of Halema‘uma‘u.

View of a clear blue hot spring pool of alkaline chloride fluid with silica sinter apron around it at Biscuit Basin.  This pool is generally close to the boiling temperature (200℉, 93℃) at this altitude (7200 ft, 2195 m).

Alkaline-chloride waters from an eruption of Old Faithful flow over the edge of the white silica sinter terrace into the Firehole River.  The orange coloration on the sinter terrace is due to thermophilic (high temperature) bacteria living in the warm fluids.  Old Faithful Inn is in the background, with the wooded Summit Lake rhyolitic lava flow behind.&nb

Only small amounts of sulfur dioxide (SO2) and hydrogen sulfide (H2S) are currently being released from Kīlauea, but they chemically react with each other (oxidation-reduction reaction) to form the bright yellow sulfur deposits visible on the crater walls within Halema‘uma‘u.

Microprobe laboratory in Menlo Park, California.

Argon geochronology lab in Menlo Park, California.

A scientist takes a gravity reading at a station located on the down-dropped block of Kīlauea caldera, which subsided as an intact structure, while a second gravity instrument (foreground) records data. Many of the preexisting gravity stations, which have been measured for years, survived Kīlauea's 2018 summit collapse.