GEOG 1 Lecture Notes - Lecture 25: Mercalli Intensity Scale, Queen Charlotte Fault, San Andreas Fault
Document Summary
Earthquakes result from the rupture of rocks along a fault, which is a fracture in. Energy is released in the form of seismic waves. Epicentre: point on surface of earth directly above the fault rupture. Focus: (also known as hypocentre) is the location of the initial rupture along the fault, directly below the epicentre. Magnitude: the amount of energy an earthquake releases. Recorded using an instrument called a seismograph. Magnitude is measured by the richter scale. Quantifies the magnitude of local earthquakes as the logarithm to the base 10 of the maximum signal wave amplitude recorded 100km from the epicentre. Modified mercalli intensity scale measures the degree to which an earthquake affects people, property, and the ground. Process of fault rupture/faulting, can be compared to sliding two rough boards past each other. Lithospheric plates moving past each other are slowed by friction along their boundaries, which exerts forces on rocks near the plate boundary.
