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What Do We Need to Teach and Know about Earthquakes? The Basics

What Do We Need to Teach and Know about Earthquakes? The Basics. Dr. Michael J Passow Earth2Class Workshops 27 Oct 2012. When and Where?. Earthquakes occur when sections of the crust, and sometimes mantle, suddenly shift past each other.

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What Do We Need to Teach and Know about Earthquakes? The Basics

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  1. What Do We Need to Teach and Know about Earthquakes?The Basics Dr. Michael J PassowEarth2Class Workshops27 Oct 2012

  2. When and Where? • Earthquakes occur when sections of the crust, and sometimes mantle, suddenly shift past each other • Most earthquakes are associated with movements at the boundaries of tectonic plates. Some are not associated with any known plate boundaries. http://www.chinaodysseytours.com/wenchuan-earthquake/images/earthquake-hit.jpg

  3. http://geomaps.wr.usgs.gov/parks/deform/eqepifoc297x164.gif The exact location where movement occurs is the focus. The spot on the surface above the epicenter is the epicenter.

  4. 3 types of faults • Normal faults: Rocks move past each other and retain their origin relationship.Reverse faults: Rock layer moves over a layer that was originally above it.Strike-slip faults: Rock layers slide horizontally past each another. These occur at transform plate boundaries. The most familiar example is California's San Andrea Fault.

  5. http://www.glossary.oilfield.slb.com/files/OGL98064.jpg

  6. Earthquakes create seismic waves that spread in all directions through the Earth. • P-waves— Primary or compressional waves travel fastest, and can travel through liquids and solids. • S-waves— Secondary waves or tensional waves have side to side movement, are slower, and can not travel through liquids. • L-waves— Surface waves moving with an up-and-down movement are last wave to arrive, but produce most of the damage to buildings and other structures.

  7. Earthquakes are detected with seismometers. The record is called a seismograph. • To locate an earthquake epicenter, you need the difference in P- and S-wave arrival times from three seismic stations http://www.learnearthscience.com/pages/Unit_Links/images/earthq1.gif

  8. Locating the Epicenter http://www.geo.mtu.edu/UPSeis/images/triangle.gif Draw circles around the stations representing the distance from the point of origin. The epicenter is where the three circles intersect.

  9. http://www.iris.edu/seismon/

  10. http://blogs.nationalgeographic.com/blogs/intelligenttravel/christchurch-earthquake-new-zealand-bus_32420_600x450-thumb-625x416.jpghttp://blogs.nationalgeographic.com/blogs/intelligenttravel/christchurch-earthquake-new-zealand-bus_32420_600x450-thumb-625x416.jpg Earthquakes and volcanoes present geologic hazards to humans.  Loss of property, personal injury, and loss of life can be reduced by effective emergency procedures.

  11. Earthquakes and Energy • Earth systems have internal and external sources of energy, both of which create heat. • Many processes of the rock cycle are consequences of plate dynamics.  These include: production of magma (and subsequent igneous rock formation and contact metamorphism) at both subduction and rifting regions; regional metamorphism within subduction zones….

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