10-9 lecture - 3. Oceanic crust melts into magma 4. Magma...

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October 9, 2007 Lecture Tectonic and Landforms Below, crust, Below lithosphere, is the liquid asthenosphere Earth works much like a convection over, the core is hot enough for convection through the mantel Patterns of landscape on earth are a result of plate tectonics Pangea, continents placed together, existed 275 million years ago Ocean and continent can be part of the same plate Transform fault: plates side by side, moving opposite direction East Africa has a rift that is slowly getting “ripped” apart and there will soon an ocean where the rift is Convergent Margin: Where two continental plates are moving towards each other and colliding Suture zone: uprise in land from colliding plates Definition: hogback ridge, anticlinal ridge and valley Subduction Margin: where we are getting rid of oceanic crust 1. Oceanic crust moves toward continental crust 2. Subduction of dense oceanic crust below lighter continental crust
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Unformatted text preview: 3. Oceanic crust melts into magma 4. Magma rises through cracks in continental crust Earthquakes: most severe earthquakes (and volcanoes) occur near plate collision boundaries So much money is put into seismology because we want to track atomic and nuclear bomb activity Earthquakes: the energy released by an earthquake is measured by the Richter scale Large earthquakes occurring near developed areas can cause great damage Richter scale is 1-10, each step up is ten times bigger: 6 to 7 is 10x, 6 to 8 is 100x, 6 to 9 is 1000x Crater Lake, Oregon: formed when a volcano erupted and the walls collapsed inward Volcanoes sit at the middle of plates in Yellowstone and Hawaii, due to hot spots in the core, caused when plates where dragged over the hot spot, causes linear chains of volcanoes Formation of the islands of Hawaii is a great example of the Pacific plate moving over a fixed hotspot...
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10-9 lecture - 3. Oceanic crust melts into magma 4. Magma...

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