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Volcanoes and Volcanism

Volcanoes and Volcanism. GLY 2010 – Summer 2012 – Lecture 8. Eruption of Mt. Vesuvius, Italy. Volcano. A vent in the surface of the Earth through which magma and associated gases and ash erupt Also, the form or structure, usually conical, that is produced by the ejected material

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Volcanoes and Volcanism

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  1. Volcanoes and Volcanism GLY 2010 – Summer 2012 – Lecture 8 Eruption of Mt. Vesuvius, Italy

  2. Volcano • A vent in the surface of the Earth through which magma and associated gases and ash erupt • Also, the form or structure, usually conical, that is produced by the ejected material • Plural: volcanoes • Etymology: the Roman deity of fire, Vulcan

  3. Pyroclastic Eruptions • Magma spews upward with great force through a central vent Left: Mt. St. Helens, 1980 Right: Kilauea, Hawaii

  4. Fissure Eruptions Video • Volcanic eruptions may occur much more quietly along long cracks in the ground

  5. Fissure Image • Eruptive fissure on southeast rim of Kilauea caldera, Hawaii

  6. Fissure Eruption • Mauna Loa Volcano, Hawaii

  7. Lava Flow Video • Kilauea, Hawaii, July 13, 2007

  8. Flowing Lava Video • (Upper left)Lava falls Kilauea, Hawaii • (Lower left) Fissure eruptions, Hawaii (with sound) • (Below) Lava flow damage (with sound)

  9. Columbia River Flood Basalt • Imnahu River Canyon • Photo: Stephen Reidel

  10. Columbia River Flood Basalt • Grande Ronde Basalt

  11. Pillow Basalt

  12. Pillow Flow, Hawaii • Click video to play

  13. Pillow Deltas

  14. Vesicles

  15. Scoria

  16. Lava Tube or Tunnel

  17. Nahuku Lava Tube • Thurston (Nahuku) lava tube • Near summit caldera of Kilauea Volcano, Hawaii Volcanoes National Park

  18. Lava Tube, Hawaii

  19. Lava-Sicles • Ape Cave, Mt. St. Helens

  20. Andesite Volcanoes • Nevado Ojos del Salado, Chile /Argentina frontier

  21. Andesite Lava Flow and Dome Volcan Láscar (Chile)

  22. Rhyolitic Lava • San Francisco Peaks stratovolcano, Arizona • Sugarloaf Mountain, the small dome-shaped hill in the foreground, is a rhyolite dome

  23. Tephra • General term for fragments of volcanic rock and lava that, regardless of size, are blasted into the air by explosions or carried upward by hot gases in eruption columns or lava fountains

  24. Tephra Eruption • The Puu Oo cone, the main vent for Kilauea from 1983-1986, is made of cinder and spatter from numerous lava fountains • Photograph by J.D. Griggs, U.S. Geological Survey

  25. Volcanic Ash Fall • Mount Pinatubo (Philippines - 1991)

  26. Effect on Climate • Large volcanic eruptions can block a great deal of the sun’s energy from reaching the earth’s surface • This cools the climate until the tephra particles sink to the surface

  27. Krakatau Volcano • Located in the Sunda strait between the islands of Java and Sumatra

  28. Krakatau, 1883 Eruption Sunset, Chelsea, London, 11/26/1883 William Ascroft

  29. Tephra Effects • Rabaul Town and Harbor after eruption Rabaul Town and Harbor before eruption

  30. Tephra Effects • The village of Galunggung, Indonesia, buried in volcanic ash

  31. Tephra Effects • Trees covered with volcanic ash near Mount St. Helens, Washington

  32. Nuée Ardente • A swiftly flowing, turbulent gaseous cloud, sometimes incandescent, erupted from a volcano and containing ash and other pyroclastics in its lower part; a density current of pyroclastic flow • Etymology: French, "glowing cloud"

  33. Mt. Pelée, Martinique

  34. Location of Mt. Pelée

  35. Eruption of Mt. Pelée

  36. Mt. PeléeNuée Ardente Photograph of a pyroclastic flow by Heilprin, 1902

  37. St. Pierre After Eruption • Photograph of the remains of St. Pierre by Heilprin, 1902

  38. Later Eruption • Ash cloud above Mt. Pelée • Photograph of Mt. Pelée by Heilprin, August 30, 1902

  39. Mt. Pelée Now

  40. Stratovolcano • A volcano that is constructed of alternating layers of lava and pyroclastic deposits, along with abundant dikes and sills • Synonym: composite volcano; composite cone

  41. Mt. Fuji, Japan

  42. Arenal Volcano, Costa Rica

  43. Movies of the eruption of Mt. Ruapehu, New Zealand, 1995

  44. Crater Lake, Oregon • Crater Lake, despite the name, is a caldera, formed after the eruption of ancient Mt. Mazama about 6600 y.b.p.

  45. Cinder Cone • Wizard Island, within Crater Lake, is a cinder cone, and one of the tallest in the world

  46. Effusive Eruptions • Shield • Central vent • Fissure • Submarine

  47. Shield Volcano • A volcano in the shape of a flattened dome, broad and low, built by flows of very fluid basaltic lava or by rhyolitic ash flows • Shield volcanoes are the largest volcanoes on Earth that actually look like volcanoes (i.e. not counting flood basalt flows)

  48. Hawaiian Shield Volcanoes These are the largest volcanoes on Earth

  49. Mauna Loa

  50. Volcanic Vent Image • Small lava fountain erupts from a new vent on the flank of Pu`u `O`o spatter and cinder cone on the east rift zone of Kilauea Volcano, Hawaii

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