VOLCANIC ROCKS AND PROCESSES
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Tumuli in basalt flow, Iceland

Tumuli in basaltic lava flow, Iceland, showing fractured outer surfaces (180912-173)
Download ImagePyroclastics of 3.5Ka Minoan eruption, Santorini

Pyroclastic deposits of 3.5Ka Minoan eruption, Santorini, Greece. Air-fall pumice at base; base-surge deposit at head level of upper most students; low temperature ash flow forms white cliffs above; high temperature ignimbrite forms gray cap. (180324-28)
Download ImageCinder cone exposed by coastal erosion

Cinder cone exposed by coastal erosion, Santorini, Greece (180324-7)
Download ImageAndesite stratovolcano, New Zealand

Mt. Ngauruhoe, a 7000 year-old symmetrical andesite stratocone in Tongariro National Park, New Zealand. (180114-47)
Download ImageLake-filled explosion crater, New Zealand

Small Lake-filled explosion crater, Waiotapu, New Zealand (180108-123)
Download ImageSulfur chimneys and fumaroles

Sulfur chimneys and fumaroles in crater of White Island, an active andesite volcanic island, New Zealand. (180110-43)
Download ImageLarge block in ash flow tuff, Colorado

Large block in ash flow tuff, Central San Juan Volcanic Field, Colorado. (160914-33)
Download ImageColumnar-jointed basalt, Oregon

Colonnade in basalt of the Deschutes Formation. Cove Palisades State Park, Oregon. (171007-43)
Download ImagePillow basalt, Olympic Mountains, Washington

Pillow basalt of the Eocene Crescent Formation (Siletz Terrane), Olympic National Park, Washington (150911-29)
Download ImageMt. St. Helens stratovolcano, Washington

View of Mt. St. Helens stratovolcano from near Johnston Ridge Observatory, Washington. Photo shows the crater, lava dome, and devastation area from the 1980 eruption. (150801-27)
Download ImageLava Flows of Columbia River Basalt Group, Washington

Lava Flows of Grande Ronde and overlying Wanapum basalts and deeply incised Palouse River, Washington (150703-38)
Download ImageBandelier Tuff, Los Alamos, New Mexico

1.14 million year Bandelier Tuff erupted from Valles Caldera, New Mexico. (160909-12)
Download ImageThurston Lava Tube, Hawaii

Thurston Lava Tube on Kilauea volcano, Hawaii Volcanoes National Park, Hawai’i. (170920-165)
Download ImageFlowing pahoehoe, Hawaii. (vertical)

Flowing pahoehoe lava flow, Hawaii. Profile of Kilauea shield volcano in background. (ID: Vc-37)
Download ImageCascade Volcanoes, Washington

Aerial view of Mt. St. Helens and Mt. Rainier, Washington (Image ID# Vc-07)
Download ImageCross-section of cinder cone, SE California.

Vertical cut through cinder cone, SE California. M-93
Download ImageCinder cone and flow, California

Cinder cone and basalt lave flow, Lassen National Park, California (Ig-91)
Download ImageCrater Lake and Wizard Island, Oregon

Crater Lake and Wizard Island, Oregon –a caldera and post-collapse cinder cone. Crater Lake National Park. (Ig-51)
Download ImageRhyolitic obsidian flow, Oregon.

Aerial view of Rhyolitic Obsidian Flow, Newberry Volcano, Oregon. Ig-49.
Download ImagePhreatic explosion crater. Death Valley, CA.

Phreatic explosion crater. Ubehebe Crater, Death Valley National Park, California. (Ig-107).
Download ImageAsh Flow tuff, Crater Lake, (vertical)

Ash flow tuff from caldera-forming eruption of Mt. Mazama to form Crater Lake about 7700 years ago, Crater Lake National Park, Oregon. The ash flow deposits erode into Pinnacles. The pinnacles are more resistant to erosion than the surrounding rock because of precipitation of minerals from gas escaping from the ash flow. (5D-8664)
Download ImagePyroclastic rock, Oregon Cascades

Pyroclastic Rock, Oregon High Cascades. Three Sisters Stratovolcanoes in background. (140902-87)
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