GEO 303 Lecture Notes - Lecture 12: Elastic-Rebound Theory, Richter Magnitude Scale, Seismometer
14 Nov 2016
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Document Summary
What is seismology?- frequency of earthquakes happens at the same continuous rate: study of seismic waves: ground vibrations produced by the rock movement along faults (or man-made explosions) Earthquakes and faults: earthquake: seismic event generated by a sudden shift of rocks across a fault, rocks under stress fail when stress exceeds strength. Strain results from stress: the relative change in the shape (deformation) due to the externally applied forces. Blocks slip suddenly, rocks snap back into place, and stress is temporarily relieved. Measuring earthquakes: magnitude: measurement of relative size of an earthquake. Richter magnitude: logarithm of largest ground motion registered by a seismograph. Relative sizes of earthquakes: each jump from one number to the next is. Used for simplicity; wide range of earthquakes easily distinguishable with. Moment magnitude (mw) proportional to area of fault rupture and seismic energy released. Intensity: indicates amount of shaking and destructiveness surrounding epicenter (subjective: seismographs and seismograms, time-distance graph, earthquake magnitude intensity, earthquake destructiveness.
