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Shield Volcano – Mafic Lava See how dark the rocks are & how flat the volcano is!

Shield Volcano – Mafic Lava See how dark the rocks are & how flat the volcano is!. Basic Facts for Shield Volcanoes. Viscosity – low Gas Solubility – low Minerals – Ca feldspar, Olivine & Pyroxene Rocks – Basalt Magma type – Mafic Boundary – Divergent. Lava Tubes.

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Shield Volcano – Mafic Lava See how dark the rocks are & how flat the volcano is!

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  1. Shield Volcano – Mafic LavaSee how dark the rocks are & how flat the volcano is!

  2. Basic Facts for Shield Volcanoes • Viscosity – low • Gas Solubility – low • Minerals – Ca feldspar, Olivine & Pyroxene • Rocks – Basalt • Magma type – Mafic • Boundary – Divergent

  3. Lava Tubes

  4. Pahoehoe –rocks that are ropy & smooth.

  5. Aa – Blocky, sharp, rocks (They got their name because they hurt when you walk on them barefoot.)

  6. Flood Basalts happen when a Shield volcano pours out very large amounts of lava. Located in Washington, Oregon & Idaho this flood covers 63,000 square miles. Up to 3000’ thick

  7. Fissure Eruptions, Curtains, and fountains – These are all “calm” volcanic features! Fissure Fountain Curtain Of fire

  8. Hawaiian Eruptions • Calm • Fluid Lava Flows • Out-pouring of basaltic lava

  9. Pele’s, the Hawaiian Goddess of Fire, Tears & Hair Hair Tears

  10. Fissure Eruption, Fire Curtain – Iceland 1996 Not always friendly!

  11. Iceland – Laki 1783; huge flood basalt from a fissure eruption, caused an “Iceland Haze” of poison gas of fluorine which killed all the crops & livestock which caused 9000 people (1/4) of Iceland population to die.

  12. Ediface Collapse – this is on the edge of the Pacific Ocean

  13. Fumarole: aka: Poison gas 1986 Cameroon Africa – Lake Nyos Gas killed all living things in a 15 mile radius including 1,700 people.

  14. Cinder ConesHot – the same as Shield Volcanoes except they are rock pieces & not lava flows! Paricutin Puu Oo – Hawaii Parasitic –

  15. Strombolian • short-lived, • explosive outbursts of pasty lava • Do not make pele’s tears or hair • dominated by scoria/tephra fragments • little or no flowing lava

  16. Composite Volcano – Felsic & Intermediate Lava

  17. Basic Facts - Composite • Viscosity - high • Gas Solubility - high • Minerals – quartz, m.mica & K-feldspar • Rocks - granite • Boundary – convergent (continent to ocean or ocean to ocean) • Magma - felsic

  18. Plinian Eruption – Huge plumes of ash thrown into the Stratosphere. • Vesuvius – 79 AD • 2000 people died – covered in ash • Mt. St. Helen’s – 1980 • 57 lives lost

  19. Mt. Pelee, Nuee Ardenteaka: Pyroclastic Flows, pelean Mt. Pelee 1902, 26,000 lives lost

  20. Nuee Ardente nuées ardentes – “glowing clouds”, “ glowing hurricane” – blistering torrents of steam, ash, pumice, and red-hot rock that were coughed from craters and charged down volcanic slopes, obliterating everything in their path. 400 degree dust & ash moving over 100 mph

  21. Laharsaka: flood Mud Flow Debris Flow

  22. Lahar at Mt. St. Helens • The lahar carries away a bridge spanning the Toutle River about 20 miles downstream from Mount St. Helens volcano on May 18, 1980.

  23. Deadly Lahars from Nevado del Ruiz, ColombiaNovember 13, 1985 • Río Lagunillas, Within four hours of the beginning of the eruption, lahars had traveled 60 miles and left behind a wake of destruction: more than 23,000 people killed, and most of the town destroyed. ember 13, 1985

  24. Tephra aka:flying rock pieces Ash Bombs Block

  25. Fumarole: aka: Poison gas Happen at Convergent boundary Volcanoes also.

  26. Rhyolite Caldera Complex Magma - felsic Rocks - granite Viscosity – very high Gas Solubility – very high Minerals – quartz, m.mica, k-feldspar

  27. Krakatoa-phreatic explosionaka:steam eruption

  28. Krakatoa 36,000 lost their lives in 1883 most deaths caused by tsunamis which hit 295 towns Could be heard from 1000 miles away. Recordable sound waves circles the earth 7 times lasting 5 days. Ash fell 300 miles away in Singapore. Rafts of floating pumice thick enough to support people crossed the Indian Ocean in 10 months and were still afloat two years after the eruption.

  29. Tambora • The caldera is over 3,000’ deep • And 5 miles in diameter Killed 100,000 people 15,000 directly & the rest due to starvation

  30. Rain, Rain Go Away - Ireland experienced persistent cold rain for 142 of the 153 summer days. The cold weather destroyed their wheat, oat and potato crops. • Hungary, January 1816 - Brown Snow?In January 1816, a blizzard of brown snow hit Hungary. • Britain, Autumn 1815 - In response to the food shortage caused by the “Year without Summer”, the British government abolished income taxes in 1816. Tambora A Year Without Summer

  31. Yellowstone National ParkPerhaps the largest volcano in the USA

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