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• Shield Volcano- broad, gently sloping volcano formed by quiet eruptions of basaltic lava. • Composite Volcano-volcano built by alternating explosive and quiet eruptions that produce layers of tephra and lava; found mostly where Earth’s plates come together and one plate sinks below the other. • Cinder Cone- steep –sided, loosely packed volcano formed when tephra falls to the ground. Shield Volcano broad, gently sloping volcano formed by quiet eruptions of basaltic lava. • Kilauea (Hawaii) • Mauna Loa (Hawaii) • Etna (Sicily) • Piton de la Fournaise (Reunion) • Erta Ale (Ethiopia) • Fernandina and all Galapagos volcanoes • Nyamuragira (Congo) • Karthala (Indian Ocean) • Savai’i (Samoa) • Aoba (Vanuatu) Composite Volcano Volcano built by alternating explosive and quiet eruptions that produce layers of tephra and lava; found mostly where Earth’s plates come together and one plate sinks below the other. • • • • Mount Fuji-Japan Mount Cotopaxi- Ecuador Mount Hood- Oregon Mount Rainier and Mount St. Helens- Washington Cinder Cone steep –sided, loosely packed volcano formed when tephra falls to the ground. • California Cinder Cones • Cerro Negro, Nicaragua • Lava Butte, Oregon • Newberry Caldera Vicinity, Oregon • New Mexico Cinder Cones • Paricutin, Mexico • Portland Vicinity, Oregon • Sunset Crater, Arizona • Wizard Island, Crater Lake, Oregon Why do volcanoes occur? The reason volcanoes occur is because when the Earth’s plates pull apart they cause magma to rise to the surface. Volcanoes can also occur above hotspots and where one plate goes beneath another, forcing the magma to rise above the surface. Where do volcanoes usually occur? Volcanic eruptions occur in certain place and don’t randomly occur. The reason for this is because the Earth’s outermost shell. (The lithosphere) is broken into a series of slabs known as lithospheric or tectonic plates. These plates are rigid, but they float on the hotter, softer layer in the Earth’s mantle. Magma The hot temperatures inside the Earth’s mantle can melt rock; creating magma. • Magma can reach up to 700 and 1300 degrees Celsius depending on the chemical composition of the rocks. • All igneous rock found on the Earth was originally formed as magma. Lava is the molten rock that comes out of volcanoes during eruptions • Lava can range in temperature from about 750 degrees C to more than 1100 C. • The temperature of the lava actually depends on the composition of the minerals in it. Some contain large amounts of aluminum, potassium and calcium, while others have iron and magnesium. What is the difference between lava and magma? • Magma is a liquid rock inside a volcano • Lava is a liquid rock (magma) that flows out of a volcano. Types of rocks formed when magma and lava cool and how. • Igneous rocks are formed from the molten liquid minerals that lie below the earth’s crust. They’re formed from magma that cools beneath the earth’s surface or from lava that cools upon the earth’s surface. • Lava cools quickly and forms rocks with small crystals. They are called extrusive igneous rocks. Basalt is an example of this type of rock. Obsidian is an example of another extrusive igneous rock that cooled so fast that it has no crystals and looks like shiny, black glass. Types of Igneous Rock features formed from volcanic activity. • Extrusive (volcanic) - produced when magma flows on the earth's surface • Intrusive (plutonic) - produced when magma solidifies at depth beneath the earth. • Silica • Obsidian • Feldspar • Quarts • Amphiboles • Pyroxenes • Olivine • Mica • Basalt Granite Mount Erebus • Location- East Antarctica • Summit - 3,794/ 12,447 • Hazards/Damage- Lava flows, some minor explosions from Strombolian-style eruptions, tephra/ash fall. • Last known eruption- Start Date- December 1972 (on or before) Stop Date- 2011 (in or after) January 14th, 2011 but is erupting as an open vent system. Persistent current activity. • The volcano always has hot gas and lava , creating surreal caves and towers. Has ice caves and a pool of lava (one of the few of its kind)