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Ash covered snow is a result of wind direction, resulting in left portion of cone free of ash while the right portion is covered. Snowstorms later covered these ash layers, which in turn were covered by new ash. The result was many alternating layers of snow and ash.

View from the northwest of a phreatic eruption on Mount St. Helens pre- May 18, 1980 eruption.

View looking west of Mount St. Helens' summit after several small explosive eruptions. The smaller of the two pit craters was formed first on March 27. Subsequent eruptions opened the farther crater.

An east-west fault across middle of summit area and an uplift or bulge on upper north flank of the volcano are also visible in this photo.

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.

Susan Russell-Robinson with USGS Deputy Director Joe Cragwall at a National Archives exhibit marking the 100th anniversary of the USGS in 1979.

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.

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.

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.

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.

Photograph from summit of San Jacinto Peak looking north across San Gorgonio Pass toward San Gorgonio Mountain. San Gorgonio River and Interstate Highway 10 traverse the Pass lowland; the Whitewater River drains the San Bernardino Mountains and flows eastward into the Salton Trough.

(Left) Aerial photograph of the Pāhala area, on the southern side of the Island of Hawaiʻi, taken on December 11, 1976. (Right) The backside of the same photo showing labeled field locations, marked with a pinhole through the photograph, which correspond to the geologist’s field notes. 

Meteor Crater formed approximately 50,000 years ago by the impact of a 100,000-ton iron-nickel meteorite, ~30 m in diameter, which struck at an approximate speed of 12-20 km/sec.

Morning Glory Pool used to be clear blue in color, as shown in the historic undated photo on the left (National Park Service photo by Rentchler).

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.

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.

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.