D2l questions 6-8

Question 1

Why was continental drift rejected?

Answer 1

Wegener couldn’t explain why there were floating continents, inadequate mechanism.

Question 2

What are the three types of plate boundaries?

Answer 2

Divergent, transform, convergent

Question 3

Why do the plates move?

Answer 3

Plates at our planet’s surface move because of the intense heat in the Earth’s core that causes molten rock in the mantle layer to move.

Question 4

why do oceans form where they do?

Answer 4

sea floor spreading

Question 5

At what type of plate boundary do very large mountains form? Why?

Answer 5

Convergent, Because the plates collide

Question 6

What is the driving force for a volcanic eruption?

Answer 6

Gasses bubbling out of solution in the magma; Plate Tectonics

Question 7

Why are some volcanoes more explosive than others?

Answer 7

Magma, viscosity, residence to flow, temperature, amount of water, composition, amount of silica in the magma,

Question 8

What are the two types of seismic waves, and which type is most destructive?

Answer 8

Body waves, surface waves. Surface waves more destructive

Question 9

Why are magnitude scales more commonly used to measure EQ strength than are intensity scales?

Answer 9

When using intensity scales, the intensity varies with distance from the focus. When using magnitude scales it measure the amplitude along with calibration for distance.

Question 10

What determines the amount of damage that a particular earthquake will cause?

Answer 10

Time of day, the population density, building design, the type of sub straight structures

Question 11

Why do seismic waves travel through some earth materials with higher velocities and through some materials with lower velocities?

Answer 11

Because the p waves are the primary waves so they have high viscosity. So the s waves are the secondary waves so they travel a lot slower.

Question 12

What is the difference between absolute and relative geologic time?

Answer 12

Relative is places events in the order they occurred. Absolute is numerical time- actual # ratio metric dating

Question 13

What causes the sudden release of energy along a fault that results in an earthquake?

Answer 13

Plate movement, movement in different directions, blocks are locked, elastic energy over comes friction

Question 14

What are the two types of body waves, and which type is transmitted only through solids?

Answer 14

P and S waves; S waves

Question 15

Volcanoes are most common at which type of plate boundary?

Answer 15

Convergent

Question 16

What are the two types of body waves, and how do they move?

Answer 16

P and S waves; p are pressure waves, fast, high velocity. S are shear and travel like scissors, slow

Question 17

What does the difference in arrival times between P and S waves on a seismogram tell us about a particular earthquake?

Answer 17

How far the away earthquake is.

Question 18

How do we know that the outer core is a liquid?

Answer 18

Because the s waves only go through solids and the earthquake doesn’t feel so far away.

Question 19

Even though we have no direct physical evidence from deep within the earth, how do we know so much about the properties and composition of the earth’s interior?

Answer 19

We look at the body waves

Question 20

Why is the silica content of magma significant for volcanic eruptions?

Answer 20

It determines the viscosity; more = high less = low

Question 21

How cans a volcanic eruption change climate?

Answer 21

Volcanic ashes in atmosphere makes the climate change makes colder and dryer, it makes the sun unable to go through the ash.

Question 22

What comes out of a volcano during an eruption?

Answer 22

Volcanic ash, Magma

Question 23

How and where do stratovolcanoes form?

Answer 23

Seductions zones; very large dangerous mountains, have eruptive cycles.

Question 24

What is the greatest hazard associated with stratovolcanoes, especially for people who live some distance from the volcano?

Answer 24

Landslides, mudflows and lava flows

Question 25

What are the two types of surface waves?

Answer 25

Love and Rayleigh; love move side to side Rayleigh forward rolling motion

Question 26

What is a tsunami and how do they form?

Answer 26

A series of water waves, caused by the displacement of large volume of a body of water.

Question 27

Why are tsunamis so destructive?

Answer 27

Large oceanic wave, generated by an earthquake, because of the high velocity on the shoreline they make a very high wave wall and floods.

Question 28

What is the seismic gap method?

Answer 28

A section of faults that has produced earthquakes in the passed but is now quiet.

Question 29

How do scientists locate the epicenter of earthquakes?

Answer 29

Through the p and the s waves looks at the distance between the arrival times. Also determines the distance in distance graphs.

Question 30

What are the principles of relative time?

Answer 30

Super position, cross cutting, fossil succession.

Question 31

What is the geologic time scale?

Answer 31

Calendar of earth’s history

Question 32

What two layers, which consist of the outer part of the mantle and the crust, are most involved in plate tectonics?

Answer 32

the lithosphere and the asthenosphere

Question 33

Why is ocean crust subducted beneath continental crust at convergent boundaries?

Answer 33

it is more dense

Question 34

What causes the sudden release in energy that results in an earthquake, and how is this energy transmitted away from the focus of the quake?

Answer 34

elastic rebound and snap-back which generate seismic waves