EES 1030 Lecture 4: Lecture 4 1:26:17 Earth Science
11 May 2017
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Document Summary
Pressure: the force per unit area exerted on an object. Elastic strain: change in rock shape resulting from stress will be reversed when the fault plane slips (rocks will return to original shape) Seismic waves: elastic waves that travel through earth; can also be generated by volcanoes, landslides, nuclear testing, mining explosions and impacts. Focus (hypocenter): site of initial rupture within earth"s crust where energy is released from. Epicenter: where earthquake is started above ground, directly above the focus. Seismic waves (two classes of waves, four types) Body waves: travel through earth"s interior (p)rimary and (s)econdary waves. Velocity varies as the properties of the material they are passing through changes (such as density, elasticity, composition, pressure and temperature). When waves pass from one material into a different material, they can be bent (refracted) and may also bounce off of it (re ected). Primary waves: compressional or push-pull waves; fastest seismic waves (6 km/s)
