GEOG 1350 Lecture Notes - Lecture 2: Mercalli Intensity Scale, San Andreas Fault, Richter Magnitude Scale
21 Oct 2017
School
Department
Course
Professor
Document Summary
They result from the rupture of rocks along a fault. Energy from an earthquake is released in the form of seismic waves. They are mapped according to the epicenter; the focus is located directly below the epicenter. They are measured by seismographs and compared by magnitude. The magnitude of an earthquake is expressed as a number to one decimal place. Today, earthquakes are measured using the moment magnitude scale (m). the scale is determined by: The amount of movement along the fault. The elasticity of the crust at the focus. Similar to the richter scale, it is a logarithmic scale. Example: an m7 earthquake represents 10 times the amount of ground motion as an m6 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 chile in 1960. In canada it is m8. 1 in bc in 1949.
