Images

The Hawaiian Volcano Observatory perched on the west rim of Kīlauea Volcano's summit caldera, overlooks Halema‘uma‘u Crater, where a new vent that opened in March 2008 emits a volcanic gas plume.

Lidar instrument uses light pulses to measure distances to the ground surface in the Kīlauea Caldera, Hawaii. Measurements are used to make a Digital Elevation Model - a very accurate topographic map.

Narrow Gauge spring, Mammoth Hot Springs, Yellowstone National Park.  Vent area is between the two trees on top of the travertine deposits.  Terraced pools form due to deposition of travertine from the fluids as they cool and degas carbon dioxide.

Incandescent arcs trace the path of lava fragments cast out during a tephra-jet explosion at the Waikupanaha ocean entry in 2008. This is a relatively small explosion, reaching a few tens of meters (yards) height, while one earlier in the day was nearly 70 meters (230 ft) in height.

When lava from the Pu'u 'Ō'ō-Kupaianaha eruption, active since 1983, meets the ocean, large littoral explosions can result.

Crater Lake Caldera with Wizard Island cinder cone and lava flows, some of the youngest features in the caldera as seen from Merriam Point. Viewed toward the south. Oregon

The early morning helicopter overflight of the lower East Rift Zone shows lava continuing to enter the sea at Ahalanui. The southern margin of the flow remains about a quarter mile from the boat ramp at Isaac Hale Park (jetty visible in the center left of the photo). View to the northeast.

Clear day during tradewind conditions at the summit of Kīlauea Volcano, Hawai‘i

Gas plume rising from Halema‘uma‘u Crater, Kīlauea Volcano, Hawai‘i

Gas plume from Halema‘uma‘u Crater from the overlook at Jaggar Museum, Kīlauea Volcano, Hawai‘i

Volcanic-gas plume rises from Halema‘uma‘u Crater, Kīlauea Volcano, Hawai‘i

A plume of volcanic gases (chiefly water vapor, carbon dioxide, and sulfur dioxide), tiny lava and rock particles, and droplets drifts southwest in the tradewinds from Halema‘uma‘u Crater.

Photograph of the Old Faithful Geyser erupting in Yellowstone Nationl Park. Old Faithful was named in 1870 during the Washburn-Langford-Doane Yellowstone expedition and was the first geyser in the Park to be named.

May 2, 2008, Chaitén volcano in Chile erupted with an ash column that rose to about 17 km (10 mi) and lasted for 6 hours. Activity continued into 2009, including this ash emission on May 27, 2008.

View of Chaitén lava dome looking north, on May 26, 2008. Note simultaneous explosion and effusion of new lava on left-central side of dome. Caldera is about 3 km wide.

All visible streets and the nearby airport were buried in 3 to 6 feet of mud, and the city harbor was destroyed.

Gas plume drifts southwest in the tradewinds over the Halema‘uma‘u Crater parking lot and Crater Rim Drive. View is toward the east-northeast. From left to right, the broad cones on the skyline are Pu‘u ‘Ō‘ō (note steam plume), and the Kane Nui o Hamo and Mauna Ulu shields.

U.S. Geological Survey's Hawaiian Volcano Observatory perched on the rim of Kīlauea Volcano's summit caldera, Hawai‘i

Close view of the USGS Hawaiian Volcano Observatory (right, with viewing tower) and National Park Service Jaggar Museum and overlook (left) on Kīlauea Volcano's caldera rim. At least three fault blocks can be seen below the observatory, which developed when Kīlauea's summit collapsed about 500 years ago to form the present-day caldera.

This section of Crater Rim Drive in Hawai‘i Volcanoes National Park was closed in February 2008 because of the high concentration of volcanic gas blowing across the road from Halema‘uma‘u Crater by prevailing trade winds. The concentration of sulfur dioxide gas in this area is considered hazardous to human health.

Volcanic air pollution, commonly called volcanic smog or vog, at the summit of Kīlauea Volcano created by the gas plume rising from Halema‘uma‘u Crater during slack tradewinds. High vog levels result in regionally hazy sky conditions that degrade air clarity and reduce visibility for everyone.