Earth Sciences 2240F/G Lecture Notes - Lecture 4: Continental Crust, Earthquake Prediction, Oceanic Crust
17 Dec 2017
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Document Summary
We accept the definition of an earthquake to be the ground shaking that accompanies a sudden movement on a fault. In nature, when the resistance across the break or fracture is overcome, the blocks. Jump along the fault plane to new positions. It is the release of that energy that produces and earthquake. Studies in labs suggests that rocks respond in two manners when subjected to stress- prior to fracturing that is. At low applications of stress, the rock will deform but as soon as you release the stress the deformation disappears; that response is termed elastic. If however, you impose still greater stress, the rock will deform to the point that, not all the deformation disappears; that"s termed plastic deformation. More stress than plastic will be released suddenly and will produce an earthquake. Rocks near earth"s surface are colder and therefore are brittle compared to rocks located beneath the surface.
