Chapter 25

Question 1

a system of mountain ranges on the seafloor separated by valleys

Answer 1

mid-ocean ridge

Question 2

long narrow depression that forms between peaks along the mid-ocean ridge

Answer 2

rift valley

Question 3

the boundary where two plates collide

Answer 3

convergent plate boundary

Question 4

when a thick and buoyant continental plate meets a thin and dense oceanic plate, the denser plate dives beneath the continent in a process called what?

Answer 4

subduction

Question 5

the boundary between two plates that are moving apart

Answer 5

divergent plate boundary

Question 6

this type of boundary where plates slide horizontally past each other in opposite directions

Answer 6

transform plate boundary

Question 7

a sudden movement or vibration of the ground that occurs when rocks slip and slide along enormous cracks in Earth’s crust called faults

Answer 7

earthquakes

Question 8

a crack in Earth’s crust along which rock has moved

Answer 8

fault

Question 9

a sudden release of strain energy as rock moves along a fault

Answer 9

elastic rebound

Question 10

the point of origin for an earthquake

Answer 10

focus

Question 11

the point on Earth’s surface directly above the focus

Answer 11

epicenter

Question 12

who came up with the continental drift hypothesis?

Answer 12

Alfred Wegener

Question 13

what were some pieces of evidence that supported Wegener’s hypothesis?

Answer 13

1. coastlines match up like puzzle pieces
2. they found large animal fossils
3. mountain ranges match up; rocks are made of same composition and age

Question 14

what was the name of the super continent?

Answer 14

Pangaea

Question 15

who came up with the seafloor spreading hypothesis?

Answer 15

Harry Hess

Question 16

what did he use to map the bottom of the seafloor?

Answer 16

he used sonar

Question 17

who discovered the mid-ocean ridge?

Answer 17

Harry Hess

Question 18

where on the bottom of the seafloor is the youngest rock going to be found?

Answer 18

nearest to the MOR (mid-ocean ridge)

Question 19

what are the types of plate boundaries?

Answer 19

divergent, convergent, and transform boundaries

Question 20

how do convergent plate boundaries move?

Answer 20

they come together (converge)

Question 21

subduction zones only occur with which type of plate boundary?

Answer 21

convergent plate boundaries

Question 22

what two types of crust are involved in plate movement?

Answer 22

oceanic crust and continental crust

Question 23

what are the types of land forms that can be created when oceanic and continental crust converge?

Answer 23

deep-sea trenches and volcanoes

Question 24

what land forms are created when two oceanic crusts converge?

Answer 24

deep-sea trenches and hot spots (creates islands)

Question 25

what land forms are created when two continental crusts converge?

Answer 25

mountains

Question 26

how do divergent plate boundaries move?

Answer 26

they diverge

Question 27

what are two specific examples of divergent plate boundaries?

Answer 27

MOR (only on oceanic crust) and East African Rift (only continental crust)

Question 28

how do transform plate boundaries move?

Answer 28

they slide past each other

Question 29

what is a specific example of a transform plate boundary?

Answer 29

the San Andreas fault (two continental crusts)

Question 30

how does a convection current work?

Answer 30

1. magma heats up, becomes less dense, and rises | 2. magma cools down, becomes more dense, and lowers

Question 31

what are other forces that help plate movement?

Answer 31

slab pull, ridge push, and friction

Question 32

what types of plate boundaries have shallow earthquakes?

Answer 32

divergent and transform plate boundaries

Question 33

which boundaries have deep earthquakes?

Answer 33

convergent plate boundaries

Question 34

what are the four types of stress that can be applied to rocks?

Answer 34

compression, tension, shear (two things rubbing together), and torsion (twisting) stress

Question 35

what are the types of deformation?

Answer 35

elastic and plastic deformation

Question 36

what happens to a rock if elastic deformation occurs?

Answer 36

as soon as the stress is released, it returns to its original shape

Question 37

what happens to a rock if plastic deformation occurs?

Answer 37

as soon as the stress is released, it will remain in its new shape

Question 38

what types of seismic waves are there?

Answer 38

primary waves, secondary waves, and surface waves

Question 39

which type of seismic waves moves the fastest?

Answer 39

primary wave (p-wave)

Question 40

what type of wave is a p-wave?

Answer 40

a compression wave (back and forth)

Question 41

what types of waves are s-waves?

Answer 41

transverse waves (up and down)

Question 42

what types of material can p-waves move through?

Answer 42

solids and liquids

Question 43

what types of material can s-waves move through?

Answer 43

only solids

Question 44

which waves are the most dangerous and complex?

Answer 44

surface waves

Question 45

what are the two scales that help us measure earthquakes?

Answer 45

the Richter scale and the Mercalli scale

Question 46

what does the Richter scale measure?

Answer 46

the amount of energy released

Question 47

what does the Mercalli scale measure?

Answer 47

the amount of damage caused