1. Earthquakes
Cornell Notes page 121

2. What is seismology?
The study of earthquakes

3. Earthquakes Shaking or trembling of the Earth’s surface
Creates seismic waves that flow on and through Earth
Earthquakes

4. Sudden movements in Earth’s crust
What causes
Earthquakes?
Sudden movements in Earth’s crust
Stress builds up until rock finally breaks
Volcanic activity, Landslides, and Nuclear Tests

5. Earthquakes do NOT cause the crust to move- The moving crust causes Earthquakes!!

8. Where do
Earthquakes
usually occur?
Plate boundaries and faults

11. Parts of an
Earthquake: Focus
Underground origin of earthquake

12. Earthquake: Epicenter
Parts of an
Earthquake: Epicenter
location of an earthquake directly above the focus on surface.

13. Seismograph
an instrument that measures vibrations in the ground, used to determine strength of an earthquake

14. An alternative seismic instrument…

15. The Richter Scale
Uses recordings of Seismographs to determine amount of energy released.
Scale of 1-10
Each successive unit is ten times more powerful than the one before.
A 7.0 on the Richter scale is 1000 times more powerful than an earthquake measuring 4.0.

16. The Mercalli Intensity Scale
Classifies EQ’s based on what is felt by people and the amount of damage caused
Uses roman numerals
Scale: I - XII

17. Scale II
Felt indoors by few

18. Scale IV
Felt indoors by many, outdoors by few

19. Scale VI
Felt by all, indoors and outdoors. Moved furniture

20. Scale VIII
Fright general - alarm approaches panic.

21. Scale XII Damage total - practically all buildings damaged greatly

23. What’s the largest Earthquake in the U.S.?
Alaska 115 died-- most deaths due to the tsunami
Shaking was felt earthquake of March 27, It had a magnitude of 9.2.
for an estimated 7 minutes
raised or lowered the ground approx. 56 feet in some places.
length of the ruptured fault was 621 miles.
energy released was equal to 12,000 Hiroshima-type blasts.

25. Largest in World…
Chile (1960)- 9.5