EARTHSC 2GG3 Lecture Notes - Lecture 3: Seismic Wave, Epicenter, Seismometer
16 Jun 2016
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Document Summary
Earthquake: motion or trembling of the ground caused by sudden displacement of rock. Differences in some of these factors explain why a m7. 0 earthquake in haiti (2010) killed. ~ 240,000 people, but a m6. 9 earthquake in california killed less than 70. Result from the rupture of rocks along a fault. Fault: a thin zone of crushed rock separating blocks of the earth"s crust. When an earthquake occurs on one of these faults, the rocks on one side of the fault slips with respect to the other. Energy is released in the form of a seismic wave. Epicentre: the point on the earth"s surface that is directly above the focus/hypocentre. This is usually the location where seismic waves are the most intense. This is the point where an earthquake originates. The ground ruptures at this spot, and seismic waves radiate outwards in all directions. The scale is logarithmic and based on powers of ten.
