Earthquakes

Earthquakes happen around the globe all the time because of the stresses and strains in the Earth’s crust resulting from the motions of the tectonic plates. Fortunately, most are too small to cause much damage. Yet, sometimes the stresses are large and when the rocks finally break, the energy release can be catastrophic to people living on or near active fault zones. Alaska is “blessed” with a subduction zone and several major transform fault systems that create more earthquakes by far than anywhere else in the US. This content page includes the resources you need to start building your case study for your chosen earthquake disaster! Start by watching the short YouTube videos below that give examples of devastation and the ensuing panic that can happen after an earthquake (in this example, from Christchurch, New Zealand), and some history from the 1964 earthquake that struck Alaska.

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Science Topics and Resources for Earthquake Hazards:

Week 1: Basic  science – follow the steps below to learn the basics. Week 1 assignments are given in the Case Study 1 page

1) What causes earthquakes? Plate tectonics creates forces on the lithospheric plates that stress, deform, and eventually break the rocks. Read about elastic rebound theory and watch the animation below:

2) What are faults? Faults are cracks in the Earth’s crust along which the rocks on either side of the fault move. Read about the different types of faults described in a publication by the  IRIS program. Then, watch the fault motion animations below, also provided by IRIS.

  • Strike Slip Faults

  • Normal Faults

  • Reverse Faults

3) Learn about seismic waves and how they are measured by reading the content from the Michigan Tech UPSeis website. Be sure to watch the animations linked in that source, or you can also view them on the website by Larry Braile at Purdue University, who created them.

4) Read about how seismic waves travel through Earth, travel times,  and how we measure them with seismographs, from the USGS Earthquake Hazards Program. Watch the seismograph animations below:

  • Horizontal Seismograph

  • Vertical Seismograph

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Week 2: Earthquake hazards, monitoring, damage, and mitigation-follow the steps below to learn the basics. Week 2 assignments are given in the Case Study 1 page

1) Read about locating earthquakes, estimating magnitude, and epicenter on the UPSeis and USGS websites:

2) Read about how earthquakes cause building damage, and watch animations about ground properties and liquefaction:

  • Shaking, ground properties, and building effects animation from IRIS

3) Read all of the sections in Earthquake Hazards 101  from the USGS Earthquake Hazards program.

4)  Play the Stop Disasters Game You are in charge of keeping people in a city safe during a destructive earthquake!

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Week 3  and Case Study Report – Assignment is given on the Case Study 1 and 2 pages. For Case Study 2, you are required to provide one additional paragraph comparing and contrasting your two case studies disasters.

 

 

 

 

GEOS 380