ERIC ANGATEnvironmental Science

Earthquakes

Essential Question

How do we protect ourselves from earthquakes?

Transform boundarySan Andreas fault

Convergent boundaryvolcanoes

Pacific Ring of FireEarthquake prone

Earthquakes happen because of too much stress in fault lines or a result of volcanic eruption. They are most common in the Pacific Ring of Fire.

1. In what area of our planet are earthquakes most common?

Divergent –Tensional stress

Convergent -Compressional stress

Transform-Shear stress

2. How is Earth affected by plate boundaries?

3. Which is the hanging wall and which is the foot wall in a fault?

A is the _______wall while B is the _____ wall.

hanging

foot

4. Describe the motion of the foot wall and the hanging wall in a normal fault.

Foot wall

Hanging wall

5. Describe the motion of the foot wall and the hanging wall in a reverse fault.

Foot wall

Hanging wall

Normal Fault Reverse Fault

Movement of the crust

Hanging wall goes down and foot wall goes up.

Hanging wall goes up and foot wall goes down.

Rocks break in the focus

because of too much stress!

• Deep focus-weak earthquake• Shallow focus- strong earthquake

Seismic waves

Epicenter

6. What is the location within Earth where earthquake begin?

7. Which state has the most frequent earthquakes? Why?

http://www.dailymail.co.uk/news/article-1366603/Earthquake-map-America-make-think-again.html

Alaska registers the most earthquakes in a given year, with California placing second. California, however, has the most damaging earthquakes because of its greater population and extensive infrastructure.

http://www.washingtonstatesearch.com/United_States_maps/United_States_map.html

Nuclear power plants in the United States

8. Describe the locations of nuclear power plants in the United States? Any relation with the earthquake map?

They calculate the distance and arrival time of seismic waves to determine the epicenter.

9. How do seismologists determine the location of the EPICENTER?

Breaks.

Deformed-does not return to original form.

Returns to original form or shape.

10. Stress causes Strain. What are the three types of strain?

Brittle strain

Ductile strain

Elastic strain

11. Seismic waves are produced by earthquakes. What are the three types of seismic waves?

P-wave

S-wave

Surface wave

12. Describe the movements of the three types of seismic waves?Primary Wave (fastest)expands and contracts

Secondary Wave right angle

Surface WaveRolling motion

Intensity is determined from effects on people, human structures, and the natural environment.

Magnitude measures the energy released at the source of the earthquake. It is measured with a seismograph based on the amplitude.

13. What is the difference between intensity and magnitude?

Magnitude = 1,2,3,4,5,6,7,8,9… Intensity= I, II, III, IV, V, VI, VIII, IX…

14. Which will have a higher intensity of earthquake given the same magnitude?

Magnitude 7 in Alaska

Magnitude 7 in California

California will have a higher intensity because of higher population density and massive infrastructures.

Magnitude does not change wherever you are.

15. How is the intensity affected by the distance from the epicenter?

Richter Magnitude 9 in California ( Epicenter)

Intensity VIII (California)

http://earthquake.usgs.gov/earthquakes/map/

Intensity III (Nevada) Intensity II

(Utah)

Intensity I (Colorado)

http://www.washingtonstatesearch.com/United_States_maps/United_States_map.html

Seismic waves

Epicenter

Transform boundary

Shear Stress

A.because the epicenter is directly the focus, the place inside the earth where the earthquake starts

B.because crustal plates rise and fall with the ocean tides

C.because most faults converge at the epicenter D.because millions of small movements of the

crust occur here  

16.Why are seismic waves of an earthquake more strongly felt at the epicenter of an earthquake?

17. How are we affected by earthquakes?

Liquefaction - soil turns to mud due to severe shaking of the ground.

Landslide Mudslide Avalanche

Landslide, mudslide, and avalanche all happen on a slope.

Soil and rocks Mud Snow

17. How are we affected by earthquakes?

earthquakeSeismic wave

Tsunami

Water receded

Japan 2011

Indonesia, Sumatra 2004

17. What can we do protect ourselves against the dangers of earthquakes?

Be aware! Know where to go.

18. What can we do protect ourselves against the dangers of earthquakes?

Be aware!

Know what to do and where to go.

Secure appliances, cabinets, and furniture.

19. Why are aftershocks so dangerous?

Aftershocks are small tremors that happen after the strong earthquake.

They are dangerous because they have the power to crumble buildings, roads, and bridges already weakened by the initialearthquake

While foreshocks comes before a major earthquake.

Earthquakes Hazards and Safety

Define the following terms:

a. Epicenter ( p. 499 )b. Fault ( p. 497 )c. Focus ( p. 499 )d. Primary wave ( p. 498 )e. Secondary wave ( p. 498 )f. Strain ( p. 496 )g. Stress ( p. 495 )h. Surface wave ( p. 498 )i. Magnitude ( p. 505 )j. Intensity (p. 506)

Open your textbook to page 507 to learn about earthquake intensity.