Images

Crater Lake bathymetric map showing the geology of the caldera floor with post-caldera eruptive units. Oregon

Gas bubbles through a sample bottle containing alkaline solution, allowing for separation of different gas phases.

Mount Baker summit, Washington. Coleman Glacier to the left and Easton Glacier to the right. Lower peak on the right is the edge of Sherman Crater. View to east.

View to the southeast through the area affected by the increased thermal output at Norris' Back Basin in the summer of 2003. The foreground shows steaming areas where boiling water and steam have approached the surface, resulting in increased ground temperatures.

Black Buttes stratovolcano and south side of ice-mantled Mount Baker. Aerial view northeastward. For Black Buttes, strata of the two highest crags (Lincoln Peak, left, and Colfax Peak) display opposing 308 dips that frame the gutted edifice.

_{Eruption cloud, from the east crater of Anatahan Volcano, rising to a height of about 15,000 feet, on May 10, 2003. View from the NE side of the island, looking in a southwesterly direction.}

Bathymetric map of Yellowstone Lake showing hydrothermal features in the north part of the lake, including Elliott's Crater, Mary Bay, and Deep Hole.  Colors correspond to lake depth, with cooler colors indicating greater depths.

Plantation forestry on the slopes of Mt Etna during the 2002 eruption, unaffected by several millimetres of fallen ash.

Isobars (gray) represent locus of values for dissolved H₂O andCO₂ in rhyolitic melt in equilibrium with H₂O–CO₂ vapor at 800°C and selected pressures. Isopleths represent locus of rhyolitic melt compositions in equilibrium with the given vapor compositions (20, 50 and80 mol% H₂

Quito's international airport was covered with 3-5 mm of ash from the 3 November 2002 eruption of Reventador Volcano, located ~60 miles to the east of the Ecuadorean capital. The airport was closed for 8 days while clean up took place.

MODIS satellite image of New Zealand’s North Island acquired on October 23, 2002 (https://earthobservatory.nasa.gov/images/3101/new-zealand).  Lake Taupō is located in the center of North Island.

Map of the northwestern U.S., showing the approximate locations of Yellowstone hotspot volcanic fields (orange) and Columbia River Basalts (gray). Boundary of Yellowstone National Park is shown in yellow. Modified from Barry et al. (GSA Special Paper 497, p.

Scientist from the USGS collects a gas sample into an evacuated/vacuum flas from a steam vent near the Shoshone Geyser Basin.

Collapse of Kīlauea's caldera floor has exposed South Sulphur Bank, prominent in the mid-19th century but covered as lava flows filled the caldera. The flat top of the white deposit shows how high the caldera fill reached. As the caldera floor dropped in mid-June 2018, South Sulphur Bank was again exposed.

Obsidian Cliff exposes the interior of a thick rhyolite lava flow erupted about 180,000 years ago. The vertical columns are cooling fractures that formed as the thick lava flow cooled and crystallized. The flow consists of obsidian, a dark volcanic glass.

NASA Astronaut image of Ta'u Island (Manu'a Islands, American Samoa) in the South Pacific Ocean.

About 130 mm (5 inches) of peak uplift from 1995 to 2001 is shown in this interferogram in the Three Sisters Wilderness. Magma accumulating at about 7 km (about 4.5 mi) depth is the likely cause of uplift. The area of uplift, about 20 km (12 miles) in diameter, is almost entirely within the wilderness area.

Mount Baker, aerial view to the northeast.

Sherman Crater, to the left of the true summit, at Mount Baker, Washington, aerial view to the northwest.

James (Jim) Vallance is a Geologist with the USGS Volcano Science Center. He is based at the Cascades Volcano Observatory.

Known eruptive episodes at Glacier Peak during the past 15,000 years. Each episode (depicted by a single icon) represents many individual eruptions. The ages of these episodes, in calendar years before present are corrected from dates based on a radiocarbon time scale.