EPSC 201 Lecture Notes - Lecture 8: New Madrid, Missouri, San Andreas Fault, Megathrust Earthquake
12 Feb 2016
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Document Summary
Magnitude is a measurement of size based on the maximum amplitude of seismograph waves. It is described using different scales: the richter scale (best for local measurements, near the epicenter) and the moment magnitude scale (the best measure; based on characteristics of different seismic waves and the area and displacement of fault slip) Measuring earthquake size of 5. 0 and 1000x a magnitude of 3. 0) Magnitude scales are logarithmic? (magnitude of 6. 0 is 10x a magnitude. Magnitude is related to the energy released. A magnitude of 6. 0 is equivalent to the energy of the hiroshima atomic. An increase of magnitude 1. 0 is a 32x increase in energy! bomb. Shallow: divergent and transform boundaries (slowest, most damage) Intermediate and deep: convergent boundaries (fastest, least damage) Two types of faulting typify mid-ocean ridges: normal faults at the spreading ridge axis and strike-slip faults along the transforms. Mid-ocean ridges earthquakes are shallow (less than 10km deep) and low energy.
