1. Earth Science Regents Review
Unit 3

2. What are the layers of the earth?
Crust: thin, rocky outer layer (oceanic and continental)
Lithosphere: crust and upper part of the mantle.
Asthenosphere: top part of the mantle, convection occurs within

3. Facts About the Layers
Mantle: thickest middle layer, mafic, crust dives into the mantle to melt
Outer Core: made of iron and nickel, solid
Inner Core: made of iron and nickel, liquid

4. 2) What are the different types of crust and how do they differ?
Continental crust: land crust, lighter, less dense, granite, thicker
Oceanic crust: under the ocean, darker, more dense, basalt, thinner

5. 4) Is the outer core solid or liquid? How can you tell?
Liquid; The interior temperature is above the melting point.

6. Summary: 2,000 km 3 mill atm Outer core Stiffer mantle
A) At what depth is the temperature 4,200oC ____________
Layer? ______________
B) What is the pressure at a depth of 5,000 km ____________
2,000 km
Stiffer mantle
3 mill atm
Outer core

7. What are the three types of plate boundaries?
A) convergent
B) divergent
C) transform

8. 2) What are divergent boundaries?
Type: Divergent (plates move apart)
Geologic Feature: Mid-ocean ridges
Example: Mid-Atlantic Ridge
midocean ridge
rift valley

9. Convergent Boundaries
mountains
Type: Continent-Continent convergence (plates move together)
Geologic Feature: Mountains
Example: Himalayas

10. Convergent Boundaries
Type: Continent-Oceanic convergence
Oceanic crusts sinks into the mantle and melts (subduction)
Geologic Feature: Volcanic Mountains and Trenches
Example: Andes Mountains & Peru-Chile Trench
volcanic mts.
trench

11. Convergent Boundaries
volcanic islands
trench
Type: Oceanic-Oceanic convergence (two oceanic plates come together)
Geologic Feature: Volcanic Islands and deep trenches
Example: Aleutian Islands, Aleutian Trench

12. Transform Boundaries Type: Transform (plates slide past each other)
Geologic Feature: Faults
Example: San Andreas Fault

13. How do you use p. 5 of the ESRT’s?
Aleutian Isl.
Himalayas
Andes Mts.

14. 2) What evidence is there for past crustal movement?
folding
faulting
tilting

15. Who was Alfred L. Wegener?
He proposed that the earth was a single supercontinent (Pangaea) that separated over time.

16. What evidence did he have for his theory?
N. and S. America fit together with Africa and Europe
The structure of the rocks matched perfectly with the coast of Africa and Europe
Tropical fossils were found in cold climates along the coast
Evidence of glaciation in S. America, S. Africa, India & S. Australia

17. 3) What do we know about the age of the ocean floor?
New crust is created at ridges so the oldest crust is near the continents.

18. 5) What happened to the earth’s magnetic field?
Periodically, the poles switch positions and the north pole becomes the south pole (reverse polarity).

19. 6) How do we know this happened?
The rocks of the ocean floor contain iron and their magnetic orientation keeps switching.

20. 2) What are the two types of waves?
Primary waves (P-waves): compressional waves, faster, go through anything
Secondary waves (S-waves): shear waves, slower, can only go through solids

21. 3) What is a shadow zone?
This is an area of the earth where earthquake waves cannot be detected.

22. 4) How is it created?
(a) S-waves can only go through solids so they get absorbed when they reach the outer core.
(b) P-waves get refracted when they reach the outer core.

23. How do we find the epicenter distance of one wave?
Locate the travel time along the y-axis
Go across until you hit the curve
Look down to see where they meet

24. 5) How do we find the epicenter?
Using p. 11 of the ESRT’s find the travel time, go across to the P or S curve then look straight down.
Every line = 20 sec
Every line = 200 km

25. 1) What does information from seismograph stations tell us?
One station?
Distance to the epicenter.

26. 1) What does information from seismograph stations tell us?
Two stations= two possible locations
Three stations= the exact geographic location

28. 2) What happens as the two waves travel farther away from the epicenter?
The two waves get farther apart because the P-wave is much faster.

29. Finding the epicenter distance using two waves?
Draw two dots on a paper the number of minutes apart.
Slide the paper until the dots match the curves.
Look down to see the distance.

31. Can we answer these? 2,800 km 4,800 km 3,000 km 8,000 km
If the travel time of an S-wave is 9 minutes 40 seconds, what is the epicenter distance?______________
If the difference in arrival times of the P- and S-waves is 6 minutes 20 seconds, how far is the distance to the epicenter? ________________
A P-wave arrived at 3:32:00 p.m. and the S-wave arrived at 3:36:30 p.m. How far away is the epicenter?_____________
If a P-wave arrived at 12:02:50 p.m. and the S-wave arrived at 12:12:10 p.m., what is the distance to the epicenter?
________________
2,800 km
4,800 km
3,000 km
8,000 km

32. -Match each lettered location with the correct seismogram
Exit Card
-Match each lettered location with the correct seismogram
-If the difference in arrival times of the P- and S-waves is 5 minutes 00 seconds, how far is the station from the epicenter? A D B C
3,600 km