XIII. EARTHQUAKES

A. BASICS

1. Definition
2. Causes:
1. human factors,
2. magma,
3. faults (elastic rebound and energy release)
3. Location: 
1. epicenter,
2. focus, depth, origin underground,
3. scarp, surface break (rupture)

B. SEISMIC WAVES:

1. recording - seismograph, seismogram
2. surface waves (damage)
3. body waves -
1. P-waves, compression, primary waves, fastest
2. S-waves, shear, secondary waves, slower, not through liquid

C. LOCATION

1. time - distance graph
2. arrival time of S & P waves,
3. three stations to locate

D. MAGNITUDE

1. Richter scale, 0-8.6, amplitude, ground motion, 10X amplitude, 30X energy, 
2. Mercalli, I-XII, damage done, subjective, 

E. DAMAGE

1. ground rupture,
2. ground motion,
3. fire,
4. landslides,
5. tsunamis,
6. liquefaction

• Compare and contrast the Richter scale and the Mercalli Scale in terms of range of values, what is measured, and effectiveness. Explain how the values on the Richter scale relate in terms of amplitude and energy released.
• Explain the relationship between epicenter and focus of an earthquake. Why is the ground rupture not always located at the epicenter?
• What types of damage can be caused by an earthquake?