Earth Sciences 1022A/B Lecture Notes - Lecture 10: Richter Magnitude Scale, Epicenter, Mercalli Intensity Scale
20 Dec 2019
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Document Summary
Magnitude: a quantitative measure of the strength of and earthquake, as determined by seismographic observations (ground motion). (there are many different scales) Earthquake magnitude determined from the maximum recorded amplitude (wave height) at a station of known s-p interval time (distance) The scale accounts for the typical decrease in wave amplitude with increased distance. Each unit of richter magnitude increase corresponds to a 10-fold increase in wave amplitude and a 32-fold energy increase. The largest earthquake ever recorded occurred in chile (may 22, 1960) magnitude 9. 5. Are always of lower magnitude than the mainshock (largest magnitude) event. Foreshocks: precede or occur before the mainshock. Intensity is a measure of the effects of an earthquake on the natural and built environment. In north america, the modified mercalli intensity (mmi) scale is used (i-xii) Magnitude (m): conveys size of the earthquake: each earthquake has a particular magnitude (size, strength, energy release, many magnitude scales.
