Lecture 6: Plate Tectonics and Earthquakes

Question 1

How do we know the internal structure of the Earth?

Answer 1

Use seismic waves from EQ to image the layer in Earth’s interior
Vibrator trucks
Sending waves into lithosphere and detecting how they return to surface

Question 2

Convergent boundaries

Answer 2

Plates deform under compression at convergent zones

Question 3

Divergent boundaries

Answer 3

Plates are pulling apart under tension

Reduction in pressure on superheated asthenosphere rock - liquifies and rises

Question 4

Lateral shear/transform boundaries

Answer 4

Plates subjected to shear stress
Plates fracture to form transform faults
Plates being separated by transform fault, and by fracture zone

Question 5

Reverse dip slip fault

Answer 5

Shortening, compression, convergent boundary, uplift

Question 6

Normal dip slip fault

Answer 6

Pulling apart, extension, divergent boundary, rift

Question 7

Strike slip or transform fault

Answer 7

Right or left lateral, side-by-sude, transform boundary

Question 8

Ocean plate vs. Ocean plate

Answer 8

Subduction

Younger, warmer, less-dense will override older, colder, denser plate

Question 9

Oceanic plate vs. Continent plate

Answer 9

a) Subduction of oceanic plate

Formation of continental volcanoes

Question 10

Continent plate vs. Continent plate

Answer 10

No subduction

Question 11

Hot spots

Answer 11

Unrelated to plate movement
Isolated regions of high temperature originated deep in mesosphere
Produce excess heat, causing hotter rock with lower density to rise through mesosphere, melt near top of asthenosphere, and pass through lithosphere as magma

Question 12

Mercalli Scale

Answer 12

Intensity scale for EQ

Question 13

Fujita Scale

Answer 13

Intensity scale for tornadoes

Question 14

Torino Scale

Answer 14

Intensity scale for earth impacts