GEOL-1010 Lecture Notes - Lecture 7: Seismic Wave, Continental Crust, Samarium
27 Sep 2016
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Document Summary
Geology in the news: new insights into planetary accretion being discovered, based on looking at two elements (neodymium and samarium) in earth, meteorites, and other objects in our solar system. What causes them: motion along faults. Releases energy in the form of an earthquake. As rocks slide against each other, the stress needs to be greater than friction for them to move. Elastic deformation: rocks in the area start having kind of a ductile deformation. Rocks move and the energy released causes the earthquake. How frequent are earthquakes: very common, especially the small ones. About 1 million magnitude 2 earthquakes happen each year. About 1 magnitude 7 earthquake per month. About 10 magnitude 7 earthquakes per year. The spot directly on the fault where the motion occurred. Can be mostly below ground: epicenter. The spot up above ground directly above the focus.
