Images

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.

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.

Note the protruding logs and branches from living trees that were knocked down and carried by the lahar. Ice axe, 3 ft, shows scale. Lahars are the greatest hazard at Mount Baker.

Potential volcanic hazards at Mount Baker.

Timeline for eruptions at Mount Baker during the Holocene (12,000 years ago to present).

Map of volcanic ashfall. Areas of the United States that once were covered by volcanic ash from Yellowstone's giant eruptions 2 million and 630,000 years ago, compared with ashfall from the 760,000-year-old Long Valley caldera eruptions at Mammoth Lakes, California, and the 1980 eruption of Mount St. Helens, Washington.

Craters of the Moon, Idaho, Landsat 7 true-color image viewed from the east. Pioneer Mountain Range along the western border. Image created by NASA EArth Observatory.

Cutaway views showing the internal structure of the Earth. Left: To scale drawing shows that Earth's crust is very thin. Right: Not to scale, more detail of three main layers (crust, mantle, core).

Photograph from the southwestern wall of the Grímsvötn caldera in Vatnajökull on December, 19 1998.

USGS geochemist Bill Evans measures the temperature of a superheated (hotter than the boiling point) fumarole in Lassen Volcanic National Park.