Images

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.

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.

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.

Scientist Jonathan Godt samples a landslide headscarp in Alameda County, CA.

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.

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.

Morphology and color-shaded bathymetry of the northeastern Caribbean region. Digital data courtesy of Troy Holcombe and Lisa Taylor, National Geophysical Data Center, Boulder, Colorado.

Mount Hood lies approximately 70 km (45 mi) from Portland International Airport. Ash can cause jet engines to fail, and air traffic may be grounded during an eruption.

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

Potential volcanic hazards at Mount Baker.

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.

A bed of manganese nodules from deep offshore of the Cook Islands; photo sourced from Hein et al., 2015, taken during a Japanese research cruise in the year 2000. Nodules range from about 2 to 10 centimeters across.

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.

The marsh of Water Conservation Area 3 as seen looking north of I-75
(Alligator Alley). Spatterdock are seen in the foreground.

Flooded marshes of Water Conservation Area 3 (WCA-3), seen north of I-75
(Alligator Alley).

An earthquake along a subduction zone happens when the leading edge of the overriding plate breaks free and springs seaward, raising the sea floor and the water above it. This uplift starts a tsunami. Meanwhile, the bulge behind the leading edge collapses, thinning the plate and lowering coastal areas.

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).