MONTEREY PENINSULA COLLEGE
GEOLOGY 2
LAB 3: EARTHQUAKES & VOLCANOES
Goal: To recognize the significance of plate tectonics in earthquake and volcano formation, type, and location.
View the eastern Pacific plate tectonic map.
1.
Examine the Peru-Chile trench. How far east of the trench are the deepest earthquakes?
2.
Draw a cross-section (a view that shows a vertical “slice” of the earth) of the subducting plate. Draw your cross-section to
scale (i.e. use the same scale on the horizontal and vertical axes. Use the trench-to-earthquake distance and the
earthquake focus depth to determine the dip of the subducting plate (the angle from horizontal down to the plate).
0
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and the shallowest?
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
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Examine the other circum-Pacific plate tectonic maps to answer questions 3 through 10.
3.
Name four geographic areas where you would expect a Benioff Zone to form.
a)
4.
b)
c)
d)
c) Rift apart.
d) Accrete to a convergent
plate margin.
What is probably the ultimate fate of the Hawaiian Islands?
a) Subduction.
b) Become an ophiolite
suite.
5.
What is a hot spot?
6.
Name at least three hot spots in the Pacific basin.
7.
Are the Galapagos Islands more likely … stratovolcanoes or … shield volcanoes?
8.
Are … stratovolcanoes or … shield volcanoes more likely to compose southern Alaska and the Aleutian Islands?
9.
Explain why there are active volcanoes in Northern California but not in Southern California.
10. How deep are typical earthquakes occurring on the San Andreas fault?
earthquake foci (300 to 600 km deep)?
Why or why not?
Are there any really deep
11. How deep are typical earthquakes on divergent plate boundaries, such as the East Pacific Rise?
MONTEREY PENINSULA COLLEGE
GEOLOGY 2
12. Describe the characteristics of the two main types of earthquake body waves.
13. Describe the characteristics of earthquake surface waves.
14. Andesitic (composite) volcanoes are found at…
a) converging plate
b) diverging plate
c) transform boundaries.
boundaries.
boundaries.
Answer the following questions from the video program titled Volcanism.
d) along fracture zones.
15. On what planet is the largest volcano?
16. If 80% of the Earth’s surface is volcanic rock, where are most of the Earth’s active volcanoes located?
17. Describe one or two of the research projects being conducted at Katmai, Alaska. Include reasons why this research will
be of value to people living in volcanic regions.
18. What benefits to humanity are contributed by volcanoes?
Answer the following questions from the video program titled Earthquakes.
19. What is the main source of stress within the Earth’s crust?
20. What conditions determine whether a building will sway or shake dangerously in an earthquake or not?
21. What are the goals of the scientists working in Parkfield, California?
MONTEREY PENINSULA COLLEGE
GEOLOGY 2
22. Define the following:
earthquake: A sudden motion or trembling in the Earth,
caused by the abrupt release of stress.
volcano: A geologic feature formed by the extrusion of lava
or ejection of rock fragments from a vent.
Benioff zone
shield volcano
fault
cinder cone
magnitude
stratovolcano (composite volcano)
Richter scale
viscosity
intensity
caldera
seismometer
tuff
liquifaction
breccia
attenuation
nuée ardente