SOC 2070 Lecture Notes - Lecture 2: Mercalli Intensity Scale, San Andreas Fault, Seismic Wave

• School: University of Guelph
• Department: Sociology
• Course: SOC 2070
• Professor: Patrick Parnaby

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 epicentre; the focus is located directly below the epicentre. The magnitude of an earthquake is expressed as a number to one decimal place. The richter scale was a measure of the strength of a wave at a distance of 100 km from the epicentre. Today, earthquakes are measured using the moment magnitude scale (m). Similar to the richter scale, it is a logarithmic scale. 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. The modified mercalli intensity scale is a qualitative scale based on damage to structures and the affect on people. Earthquakes are most common at or near plate boundaries.