Images

Mount Hood dominates the skyline outside Portland, Oregon on a clear day. A major eruption of Mount Hood would pose a great hazard to the regional economy.

Volcanic Hazard Assessment for the Lassen Region, California is based upon a comprehensive investigation of the eruptive history and possible future eruption scenarios with associated volcanic hazards.

The east face of Middle Sister is 350 m (1150 ft) high. Ice-sculpted pile of lavas at right, variously called "Black Hump," "Prouty Point," or "Step Sister," has 190 m of relief and consists of at least five flows.

Aerial view of a lava tube trace (dark sinuous shape) along the ground surface at Medicine Lake Volcano, California.

Lassen Peak viewed from the south at the summit of Brokeoff Volcano, Lassen Volcanic National Park.

Map of Yellowstone National Park showing Brimstone Basin and other areas known to release carbon dioxide from the ground.

Ice Springs cinder cone and lava flow erupted 720 years ago in the Black Rock Desert Volcanic Field, Utah.

Tephra-laden water filtering through the turbines has necessitated the replacement of four turbines in 21 years. The Agoyan Dam and its (orange) floodgates are designed to let highly turbid water bypass the turbines so as to avoid accelerated wear of generation components

Summary of power system impacts following 12 historic eruptions.

Mount Hood looms above the Columbia River and Glenn Jackson Bridge. Excess sediment from eruptions of Mount Hood have choked the river and caused flooding in the past.

Mount St. Helens and the industrial waterfront area of North Portland, Oregon along the Willamette River in the foreground. Excess sediment from volcanoes can significantly impact river traffic.

"Stevens and Party at Kīlauea" - U.S. Minister Stevens is second from the right. Demosthenes Lycurgus and Alex Lancaster are first and second from the left, respectively.

This thermal image shows the scattered breakouts on the coastal plain and the ocean entry near Kupapa`u. In addition to these coastal plain flows, several breakouts were active near the top of the pali, around the northern boundary of Royal Gardens subdivision.

The ocean entry (at center of image) near Kupapa`u remains active, with a weak and wispy plume. The light colored area on the coastal plain shows the recently active flows.

A closer view of the ocean entry, with weak plumes originating from several spots along the coast.

A small collapse this morning of the spatter cone that had built up around the northeast lava pond in Pu‘u ‘Ō‘ō resulted in a brief gush of lava onto the crater floor.

Thomas Jaggar and his wife, Isabel, hiking on Mauna Loa during the September 1919 Southwest Rift Zone eruption.

A highlight of HVO's 100th anniversary in 2012 was the Centennial Poster Contest for Hawai‘i Island 4th grade students. The poster shown here was created by Jyron Young, who was awarded the Grand Prize for his artistic depiction of 100 years of volcano watching in Hawai‘i. Image courtesy of USGS.

Crater Lake partially fills the caldera that formed approximately 7,700 years ago during the eruption of a 12,000-ft-high volcano known as Mount Mazama.

The May 18, 1980 eruption of Mount St. Helens had a dramatic impact on the North Fork Toutle River. The debris avalanche, lateral blast and ashfall produced a substantial amount of sediment, which continues to be washed into the river and transported downstream.

Logs float in Spirit Lake near the Spirit Lake gaging station and outflow tunnel. View is to the south with Mount St. Helens in the background.