earthquakes. how do we protect ourselves from earthquakes?
TRANSCRIPT
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.