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Dynamic Earth

Dynamic Earth. Class 9 7 February 2006. Any Questions?. Note: Exam #1 Date shown on hardcopy syllabus at February 14 th , but said February 15 th . The correct date is February 14 th (On-line version is correct). Elastic Rebound Theory. Elastic Rebound Theory.

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Dynamic Earth

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  1. Dynamic Earth Class 9 7 February 2006

  2. Any Questions?

  3. Note:Exam #1Date shown on hardcopy syllabus atFebruary 14th, but said February 15th.The correct date is February 14th (On-line version is correct)

  4. Elastic Rebound Theory

  5. Elastic Rebound Theory

  6. Seismograph Record and Pathway of Three Types of Seismic Waves

  7. World Seismicity, 1963–2000

  8. Plate Margin Volcanism

  9. Hawaiian Volcanism

  10. Why do some volcanoes (e.g, Augustine Volcano) erupt violently whereas other volcanoes (e.g. Kilauea Volcano) erupt relatively quietly?

  11. Monday, February 06, 2006 (Associated Press) S C I E N C E: Augustine Volcano continues to erupt Augustine Volcano continued to erupt today, with the volcano producing a continuous crescent-shaped plume of steam, and ash and gas speeding down the flanks of the island mountain and into the sea. The Alaska Volcano Observatory made hourly updates on its Web site with each one beginning the same way — “Eruption is in progress.”The volcano on an uninhabited island has been erupting since Saturday, with explosions thrusting particles almost five miles into the skies around south-central Alaska. With winds shifting the ash away from major air routes, airlines cautiously resumed dozens of flights that had been canceled as a precaution. Ash particles can damage engines. Alaska Airlines on Tuesday resumed all flights to and from Kodiak Island and Anchorage, the state’s largest air hub, said spokeswoman Amanda Tobin. The airline had canceled all of its 36 Anchorage flights Monday night as a precaution. Flights to and from Kodiak had been canceled Sunday and Monday.

  12. Volcanic Hazard

  13. Augustine Earthquake Activity

  14. Extrusive Intrusive Basalt Gabbro Rhyolite Granite Granite

  15. Classification of Igneous Rocks • Determined by composition (both chemical and mineralogical): • magnesium (Mg) + iron (Fe) = mafic • feldspar + quartz (Si) = felsic

  16. Classification of Igneous rocks

  17. Bowen’s reaction series • Series of chemical reactions that take place in silicate magmas as they cool • First investigated in the 1920s and 1930s by N. L. Bowen • Important experiments that help us understand the evolution of magmas

  18. Bowen’s Reaction Series

  19. Early Crystallization

  20. Fractional crystallization • The modification of magma by crystallization and removal of mineral phases • Because only certain elements will go into a given mineral, this will tend to change the composition of the remaining liquid

  21. Magma Differentiation

  22. Magma Chamber Beneath Mid-ocean Spreading Ridge

  23. Where do magmas come from? • Basalts: Broadly speaking, we know that mantle rocks (45% SiO2) partially melt (10 to 15%) to produce basalts (50% SiO2)

  24. Volcanism Due to Partial Melting in a Subduction Zone

  25. Where do magmas come from? • With the addition of some water, basalts will partially melt to produce Andesite (60% SiO2)

  26. Factors Affecting Melting Temperatures

  27. Tectonic Settings of Igneous Activity

  28. Volcanic Island Arc, Indonesia

  29. Hawaii Oceanic Hot Spot

  30. Continental Volcanic ArcN. Cascades

  31. 0 Tectonic Settings and Volcanic Activity

  32. Earthquake distribution defines plate boundaries

  33. December 26, 2004Earthquake off Sumatra

  34. Earthquake Focus

  35. Subsidence in Banda Aceh

  36. Subsidence in Banda Aceh

  37. Tsunami Series of very long-wavelength waves on the ocean = “tidal wave” Has nothing to do with tides /

  38. Tsunami

  39. Generation of a Tsunami

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