Week 9 – Plate Tectonics & Volcanic Processes

Question 1

What three forms of evidence did Alfred Wegener use in proposing his Continental Drift Theory and that Earth once had a single “supercontinent” we now call Pangea?

Answer 1

-Fossil record

-Close geological features on both sides of the Atlantic

-Different continent mountain ranges indicate they were once one mountain range

-Africa and S. America fit together like a puzzle

Question 2

What is the theory of Plate Tectonics?

Answer 2

The lithosphere comprises distinct tectonic plates that float on the asthenosphere and move around.

Question 3

What sub-layer of Earth’s mantle do the plates “float” on?

Answer 3

“plastic” asthenosphere

Question 4

What data has been recorded by scientists to outline the Earth’s plates?

Answer 4

Earthquake seismograph data
Volcanic Activity

Question 5

What are the three major types of tectonic plate boundaries?

Answer 5

Divergent
Transformative
Convergent

Question 6

Describe what happens when an oceanic plate and a continental plate collide with each other, and name two major (catastrophic) events that can happen as a result.

Answer 6

The oceanic plate subducts under the continental plate because it’s much thinner.

This can cause Volcanic ranges and earthquakes.

Question 7

Describe what happens in an ocean-to-ocean plate convergence happens. Which plate is likely to subduct?

Answer 7

One plate will subduct under another. with the “older and colder” plate going under.

Question 8

What is one formation that can result from ocean-to-ocean convergence?

Answer 8

Aleutian Islands

Question 9

Describe what happens in a continent-to-continent convergence scenario.

Answer 9

Since both are continental plates, neither will subduct, so they collide instead.

Question 10

Name two consequences that can happen from a continent-to-continent convergence.

Answer 10

Mountain ranges and frequent massive earthquakes

Question 11

Describe a landform that is created when two oceanic plates diverge.

Answer 11

Magma ends up welling up and creates new land or a new oceanic floor.

Question 12

Describe a landform that is created when two continental plates diverge.

Answer 12

Great rift valley

Question 13

Describe the motion or action between two plates in a transform fault zone, and name one famous transform fault in California.

Answer 13

Sliding past, one another
San Andreas Fault

Question 14

What consequences/frequent occurrences happen in transform fault zones?

Answer 14

Earthquakes

Question 15

What are areas called where rising magma through the crust forms volcanos in the middle of a tectonic plate?

Answer 15

Hot Spots

Question 16

Name two places in the U.S. where rising magma through the crust forms volcanos in the middle of a tectonic plate is happening.

Answer 16

Yellowstone Caldera, Wyoming
Hawaiian Islands

Question 17

Name and describe the two types of volcanoes.

Answer 17

Shield Volcanoes
Stratovolcanoes/Composite volcanoes

Question 18

Which type is associated with tectonic plate convergence?

Answer 18

Composite volcano

Question 19

Which type of volcano is associated with mid-plate “hotspots” or continental divergent rift zones?

Answer 19

Shield Volcano

Question 20

What is an earthquake?

Answer 20

a vibration in Earth produced by shock waves resulting from a sudden displacement along a fault

Question 21

Where do approximately 80% of all earthquakes occur on Earth?

Answer 21

The ring of fire

Question 22

What is the surface location above an initial rupture/earthquake called.

Answer 22

Epicenter

Question 23

What are two units of measurement or “scales” that quantify the strength of an earthquake? What is used to measure the strength of an earthquake?

Answer 23

Richter scale and Moment scales