Geography 2152F/G Lecture Notes - Lecture 9: Logarithmic Scale, Epicenter, Seismometer
9 Nov 2018
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The moment magnitude scale: today, earthquakes are measured using the moment. Magnitude scale (m): the scale is determined by, the area ruptured along a fault, the amount of movement along the fault. Magnitude and frequency of earthquake: except for very large earthquakes, the magnitude on the moment magnitude scale is similar to the richter. Scale: the strongest earthquake to ever occur is m9. 5 in. In canada, it is m8. 1 in b. c. in 1949: there are only a few m9+ earthquakes each century. Earthquake intensity: the modified mercalli intensity scale is a qualitative scale based on damage to structures and the effect on people. It is based on 12 categories: descriptive data. Identifying faults is necessary to evaluate the risk of an earthquake in a given area: thus, faults are considered seismic sources, not all faults reach the earth"s surface, blind faults are located below the surface.
