Dynamic Earth

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Dynamic Earth

  1. 1. Dynamic Earth Dr. Jennifer Wright
  2. 2. Shake, Rattle, ‘n Roll <ul><li>Plate Tectonics – the big picture, creation of the major geographic features of the Earth </li></ul><ul><ul><li>Layers of the Earth </li></ul></ul><ul><ul><li>Plate Boundaries </li></ul></ul><ul><ul><li>Earthquakes </li></ul></ul><ul><ul><li>Volcanoes </li></ul></ul><ul><ul><li>Impact Craters </li></ul></ul>
  3. 3. Layers of the Earth <ul><li>Inner core </li></ul><ul><ul><li>Solid Fe, Ni </li></ul></ul><ul><li>Outer core </li></ul><ul><ul><li>Liquid Fe, Ni </li></ul></ul><ul><ul><li>Creates magnetic field </li></ul></ul><ul><li>Mantle </li></ul><ul><ul><li>Magma, convection </li></ul></ul><ul><li>Crust </li></ul><ul><ul><li>Thinnest, coldest layer </li></ul></ul><ul><ul><li>Plates!! </li></ul></ul>
  4. 4. Plate Tectonics <ul><li>Framework for understanding most geographic features of the planet </li></ul><ul><ul><li>Mountain ranges, volcanoes, earthquakes </li></ul></ul><ul><ul><li>Deepest point (Marianas Trench), Highest point (Mt. Everest) caused by plate interaction </li></ul></ul><ul><li>3 kinds of plate boundaries </li></ul><ul><ul><li>Divergent </li></ul></ul><ul><ul><li>Convergent </li></ul></ul><ul><ul><li>Transform </li></ul></ul>
  5. 5. Divergent Boundaries <ul><li>Are the result of “pulling” forces </li></ul><ul><li>Have small earthquakes </li></ul><ul><li>Create many normal faults </li></ul><ul><li>Are usually on the opposite side of the plate from a convergent boundary </li></ul>
  6. 6. Convergent Boundaries <ul><li>Collision of two plates </li></ul><ul><li>Have all the large earthquakes </li></ul><ul><li>90% of all earthquakes happen here </li></ul><ul><li>Ocean-continent collisions = subduction </li></ul><ul><li>Explosive volcanoes </li></ul><ul><li>Reverse faults </li></ul>
  7. 7. Transform Boundaries <ul><li>Are the result of parallel and opposite forces </li></ul><ul><li>Have small to medium earthquakes earthquakes </li></ul><ul><li>Create strike-slip faults </li></ul><ul><li>Can cause streams to turn at right angles </li></ul>
  8. 8. Earthquakes <ul><li>Mostly happen on plate boundaries </li></ul><ul><ul><li>90% happen on convergent boundaries </li></ul></ul><ul><li>Seismographs can record earthquakes from all over the world above 2.5-3 on magnitude scale </li></ul><ul><li>Are a release of energy as two blocks move relative to each other </li></ul><ul><li>Are measured on a logarithmic scale (multiply by 10) </li></ul>
  9. 9. Volcanoes <ul><li>Mostly created by melting of oceanic plate in the subduction zone and by hot spots in the mantle </li></ul><ul><li>Explosive volcanoes associated with dissolved gases (H 2 O) in lava </li></ul><ul><ul><li>Ex. Mt. St. Helen’s </li></ul></ul>
  10. 10. Impact Craters <ul><li>Far fewer visible impacts than other planetary bodies </li></ul><ul><ul><li>Atmosphere </li></ul></ul><ul><ul><li>Oceans </li></ul></ul><ul><ul><li>Erosion/deposition </li></ul></ul><ul><li>High velocity of impacts vaporize the meteor </li></ul><ul><li>Chesapeake Bay was created by an impact ~36 million years ago </li></ul><ul><ul><li>Most earthquakes in the region today are due to settling from impact and glacial rebound </li></ul></ul><ul><ul><li>Contamination by saltwater limits the freshwater available today </li></ul></ul>
  11. 11. Classroom Activities <ul><li>Plate Boundaries </li></ul><ul><ul><li>Plot earthquakes on maps </li></ul></ul><ul><ul><li>Graph earthquakes based on depth, magnitude, and boundary type </li></ul></ul><ul><ul><ul><li>Earthquakes on convergent boundaries are deeper and larger </li></ul></ul></ul><ul><ul><li>For more advanced students, locate the epicenter using “Virtual Earthquake” </li></ul></ul><ul><ul><li>Plot volcanoes to locate plate boundaries (convergent) and hot spots (Hawaii) </li></ul></ul><ul><li>Discuss the week’s planetary events in terms of potential human impact </li></ul>

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