1. EARTHQUAKES

2. EQ facts  Largest EQ recorded in the US 9.2  Largest in world 9.5  Average rate of motion across the San Andreas Fault is 2 in./yr. (3 million years L.A. will be next to S.F.)  500,000 detectable EQ each year.  More damage is caused indirectly from the EQ, not the EQ itself.

3. EQ facts cont.  10,000 EQ’s will develop in southern Cali this year. Most will not be felt.  Powerful EQ’s rocked the midwest in the early 1800’s. New madrid fault had a magnitude of over 8 and caused church bells to ring in Boston Mass.  Deadliest in China 1557, killing 830,000 people.

4. WHAT ARE EQ’S  Vibrations of the earth’s crust.  Movement of plates along faults  Fault-crack in rock where movement occurs  Elastic Rebound Theory – Rocks of both sides of the fault are in constant movement. When these rocks lock up stress is increased. When this lock is broken an EQ occurs.

10. TYPES OF FAULTS  Normal fault – hanging wall moves down the footwall.  Reverse fault – hanging wall moves up the footwall  Strike-slipe fault – rock on either side slide past each other.

16. SIESMOGRAPH/GRAM  Seismograph – instrument used to detect earthquakes.  Seismogram – Recorded waves of an earthquake.

21. TYPES OF WAVES  P waves (primary) Compressional waves. Very fast. First to be seen on a seismogram.  S waves (secondary) Side to side. Can only travel through solids.  L waves (Long) Slowest moving. Very destructive. Rolling waves.

26. http://www.pbs.org/wnet/savageearth/animations/index.html

27. Magnitude  Richter Scale – Scale used to measure the magnitude of an earthquake. Measured by the release of energy of an earthquake.  Each increase of one whole number is 31.7 times more powerful.  Mercali Scale – Scale used to measure the amount of damage an EQ causes. Roman numerals.

31. Location  Determine the difference between the S-P lag time.  Plot the distance for 3 stations. Where your points meet is where your EQ’s epicenter is.