Images

View from the north of Mount St. Helens' eruption and first crater.

Although seismic activity began under Mount St. Helens on March 20, this overflight showed no unusual features except numerous tracks of earthquake-triggered snow avalanches. No evidence of fracturing of summit area was detected during careful visual observations on the afternoon of March 24, 1980.

Before the devastating May 18, 1980 eruption, Mount St. Helens was considered to be one of the most beautiful and most frequently-climbed peaks in the Cascade Range. Spirit Lake was a vacation area offering hiking, camping, boating, and fishing.

Mount St. Helens one year prior to the May 18, 1980, catastrophic eruption, showing glaciers at the summit.

East Dome erupted during Sugar Bowl time (C.E. 850-900) east flank view of Mount St. Helens. Kalama age (erupted about 1535) andesite flows surround dome.

Worm Complex on the southeast flank of Mount St. Helens—Middle Kalama lava flows in center of image. Photo from September 28, 1979. Click to view larger image.

Summit region (Kalama age–1479 to 1720 C.E.) of Mount St. Helens looking northeast. Spirit Lake and Mount Adams in background. September 28, 1979.

Studebaker Ridge formed during the Tertiary geologic time period (65 million to 2.6 million years ago). The pyroclastic surge from the May 18, 1980 eruption destroyed the trees on the ridge.

Before the eruption of May 18, 1980, Mount St. Helens' elevation was 2,950 m (9,677 ft). View from the west, Mount Adams in distance. S. Fork Toutle River is valley in center of photo.

Mount Adams elevation is 3,745 m (12, 286 ft). Mount St. Helens was the smallest of five major volcanic peaks in Washington State.

Three Fingered Jack (2390 m or 7840 ft) is a volcanic peak in central Oregon near Mount Bachelor and the Three Sisters. Black Butte is in the background.

Mount Konocti, a mostly dacitic composite cone, on the western shore of Clear Lake, California. Thurston Lake is in the foreground.

A M 7.7 earthquake on November 29, 1975, was located beneath the south flank of Kīlauea.

The magnitude-7.7 earthquake caused a nearly continuous zone of ground cracking and faulting for about 25 km (15 mi) along the south flank inland of Halapē.

Fractures in Crater Rim Road, Hawai‘i Volcanoes National Park, caused by the November 29, 1975, earthquake beneath the south flank of Kīlauea Volcano. Only a few meters (yards) from Kīlauea's summit crater (out of sight left of guardrails), large sections adjacent the crater wall slumped toward the crater, forming these fractures.

Ground cracks along Crater Rim Drive in Hawai‘i Volcanoes National Park caused by the M 7.7 earthquake on November 25, 1975. The cracks resulted from slumping of the ground toward the rim of Kīlauea Crater, the edge of which is left of the guardrails.

At 04:48 HST that morning, a magnitude-7.7 earthquake shook the island and generated a local tsunami that killed 2 people. Strong shaking from the earthquake produced damage at many locations on the Island of Hawai‘i. Within Hawai‘i Volcanoes National Park, sections of Crater Rim Drive (shown in this photo) cracked, some slumped toward the crater.

Mauna Loa 1975 eruption. Lava fountains up to 20 m (65 ft) high erupted from fissures on the north flank of the volcano early Sunday morning, July 6, 1975.

A three-day long eruption in July 1974 sent lava flows onto the floor of Kīlauea Volcano's summit caldera, where they spread out beneath the western caldera wall.

Low fountains and repeated overflows at the Mauna Ulu crater build the shield higher. Lava flows were mostly brief and short, thereby increasing the relief between the top of the shield and its base. The perched lava pond shown in the previous photo is bypassed by the two rivers.

Perched lava pond forming between Mauna Ulu and Pu'u Huluhulu, January 25, 1974. Several episodes of renewed growth in height of Mauna Ulu occurred in early 1974. The first sent much lava toward Pu'u Huluhulu, where a perched lava pond developed. This photo shows lava in the pond spilling over the enclosing levee and making it higher.

Note the two smaller vents on the west (left) side of the crater above the lake, which is about 150 m (500 ft) across.