Images

Angle and distance measurements to the Mount St. Helens' flanks were taken periodically to monitor for deformation similar to the 1980 bulge. Station northeast of volcano.

Ice cone at Porkchop Geyser in March 1989.

Fumaroles of cold, dry CO2 such as this one on a lava flow erupted in 1938 from Nyamuragira Volcano, Zaire, can be exceptionally dangerous because the gas discharge is invisible. The density difference between CO2 and air is so great that a sharp boundary can persist between them.

A thin-walled lava bubble expands and bursts. These "bubble bursts" occur when seawater infiltrates the lava tube system near the shore. Such bubble bursts produce translucent sheets of spatter, or limu o Pele.

Glacial end moraine deposits on south flank of Mauna Kea, Hawai‘i

The deposits are found between about the 11,000 and 12,000 ft elevation. The cinder cones left of the glacial deposits were erupted between 70,000 and 13,000 years ago, and the irregular surface below the cones and glacial deposits consist of lava flows erupted during the same time frame.

The light colored lava flows in foreground are part of the older Laupahoehoe Volcanics, erupted between 70,000 to 13,000 years ago. one of the youngest cinder cones erupted by the volcano,

12,398 ft elev according to USGS Geographic Names Information System

Pu‘u Keonehehe‘e and the two small cones immediately to the northwest (left) are among the youngest cones erupted on the volcano, as recent as about 4,000 years ago. The other cones in this view are part of the Laupahoehoe Volcanics, but much older, dating to 70,000 years ago.

Deformation measurements on the Mount St. Helens' dome; three geologists in middle bottom of this aerial photograph.

Glacial deposits of the Waihu Glacial Member exposed in unnamed gulch on southwest flank of Mauna Kea at about 3,020 m (9,900 ft) elevation. Ages of both the glacial deposits and lava flows are poorly known, estimated to within about 150,000 to 70,000 years ago. Pole is 1.5 m (5 ft) long.

Lava bubble bursts are a relatively mild form of explosion that occurs when a lava tube at, or below sea level, fractures abruptly, allowing seawater to enter the tube system. As the infiltrating seawater comes into contact with molten lava in the tube, the water is heated to steam in an instant.

Explosive interaction between lava and seawater blasts a tephra jet consisting of steam, hot water, black tephra, and molten fragments into the air. This explosion is directed primarily toward the sea, but many explosions also send a shower of lava more than 10 to 20 m inland.

Mount Adams southern view as seen from Trout Lake, Washington. Trout Lake sits on thick lahar deposits that originated as a debris avalanche 6,000 years ago.

Mount Thielsen (2,799 m or 9,182 ft) is an extinct volcano north of Crater Lake, Oregon that last erupted 250,000 years ago. Aerial view.

Mount Thielsen (2,799 m or 9,182 ft) is an extinct volcano north of Crater Lake, Oregon that last erupted 250,000 years ago. Diamond Lake is in the background.

Bystanders watch steam rising from Queens Bath as lava flow enters the water. Lava overran Highway 130 at 0748 Hawaii Standard Time on the same morning at the western margin of the Kapa'ahu flow. By the end of the day, Punalu'u heiau was overrun, and Queens Bath was filled with lava.

pāhoehoe flow advancing through mango trees toward a house in Kalapana Gardens subdivision, Hawai‘i

pāhoehoe flow crosses Highway 130 and enters Kalapana, Hawai‘i, Kīlauea Volcano

Pu‘u ‘Ō‘ō cone is visible on skyline at center. In the foreground are the Mauna Kea Congregational Church (right of center) and fishponds (lower left) bounded by the Hakuma horst, the uplifted, elongate block at lower left. View is to the northwest.