MATH 122 Quiz: Earthquakes
8 Dec 2015
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An earthquake is the result of a sudden release of energy in the earth"s crust that creates seismic waves. Rocks undergoing deformation break suddenly along a fault line. Earthquakes affect more than 35 countries, can have high death tolls (i. e. 750,000 people in "76 in china), primary feature is ground shaking, secondary phenomena (aftershocks) are fire, landslides, ground subsidence, snow and ice avalanches and floods. The earth"s surface is composed of a number of mobile tectonic plates which are in constant motion. Most earthquakes are found at plate margins. At the divergent margins two tectonic plates are in the process of being created. Magma is injected into a crack in the earth"s crust (magma is created by decompression melting of the earth"s mantle), then it cools and becomes new crust. The middle of the atlantic ocean is a divergent margin which is being torn, or rifted, apart the two plates are separating continuously at a rate of several cm/yr.
