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Images of Volcanoes and Volcanism
Images on this site are organized by the type of volcano or type of lava flow
  Categories Description (Click on picture or button to see the gallery)
Dry Falls Lava Plateaus Basalt lavas are non-viscous, meaning they flow easily, and they can spread out over a wide area. In some tectonic environments, such flood basalts can cover thousands of square miles several thousand feet deep. These lava plateaus may herald the onset of continental divergence. These pictures include scenes from the Columbia Plateau in Washington and Oregon, the Modoc Plateau in California, and a former plateau on the Isle of Skye in Scotland.
Mauna Loa Hawaiian Shields

Other Shields
Basaltic lavas flowing from hot spots like the Hawaiian Islands or from areas of crustal extension may form gently sloping volcanic cones called shields. Hawaiian-style shields are the largest mountains in the world, rising 30,000+ feet from the ocean floor. Smaller cones, called Icelandic-style shields, are found on land. Pictures in this collection include the Hawaiian Islands, and Shields in California and Oregon.
Mt. Hood, Oregon Composite Cones and Stratovolcanoes Andesitic lavas, typically derived from subduction zones at convergent plate boundaries, are more viscous, so they do not flow as easily as basalt, and can occasionally be explosive. The cones they build are steep and high. These composite cones, or stratovolcanoes, are among the most beautiful and dangerous volcanoes on the planet. This collection includes composite cones of the Cascades in the Pacific Northwest, in Arizona, Italy, and New Zealand and special pages for Mount Shasta and Mt. St. Helens.
Red Hill Cinder Cone Cinder Cones Cinders are small fragments of volcanic rocks which can be composed of basalt, andesite, and rhyolite. In small explosive eruptions, cinders can pile up into small steep cones. They are found by themselves, or on the slopes of larger volcanoes. Examples in this collection include cones in Hawaii, the Cascades, the California desert, and Arizona.
Black Butte near Mt. Shasta Plug Domes Plug domes, or lava domes, are small volcanoes composed of highly viscous lavas like dacite or rhyolite. They are sometimes found in association with large stratovolcanoes; the dome in the crater of Mt. St. Helens is an example. The largest plug dome in the world can be seen at Lassen Volcanic National Park. Others in this collection include the Inyo/Mono Craters and Medicine Lake Highland in California, Mt. St. Helens in Washington, and Newberry Volcano and Crater Lake in Oregon
Calderas Calderas are collapse features that form when large amounts of lava vacate the magma chambers beneath volcanoes. The calderas that form on shields are usually a few miles across and a few hundred feet deep. Andesite calderas may be a few miles across and several thousand feet deep. The eruptions that form them can be catastrophic. Rhyolite calderas produce some of the most violent eruptions known, leaving depressions tens of miles across and several miles deep. Pictures in this collection include calderas in Hawaii, California, Wyoming, and New Mexico.
Lava Flows The viscosity of a lava determines the appearance of a lava flow. Non-viscous lavas may have smooth or ropy surfaces called pahoehoe flows, while more viscous flows can produce blocky, rough surfaces called a'a flows. Tephra (or pyroclastic debris) is a deposit of material explosively blown from a volcano. Tephra ranges from dust particles (ash) to large chunks (blocks and bombs).
Lava Tubes One reason basalt lavas can flow great distances is that the lavas crust over and flow beneath the surface. They can flow through these highly insulated environments for miles without losing heat. When the lava stops flowing into the tubes, they drain, leaving behind these unique lava tubes. The longest tube known, in Hawaii, is 40 miles long. Lava Beds National Monument in California has more than 700 individual tubes.
Shiprock New Mexico Erosional Features Volcanoes don't erupt forever. When the subterranean fires subside, they become extinct and erode into a variety of interesting forms, including volcanic necks and inverted streams. This collection includes photos of necks in Arizona and New Mexico, and a famous inverted stream in the California Mother Lode.
Plutons and Intrusions Volcanoes are fed by magmas rising through the Earth's crust which make room for themselves by filling fractures or engulfing and melting the surrounding rocks. Intrusions, or plutons, include dikes, sills, laccoliths, stocks and batholiths.
   

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