(TEST 1) Earth Science, Lecture pt 3 (ch 6 and 7)

Question 1

What 4 settings does volcanic activity usually occur in?

Answer 1

1. Isolated hot spots/ mantle plumes
2. Volcanic arcs bordering deep ocean trenches (convergent)
3. Mid-ocean ridges (divergent)
4. Continental rifts (divergent)

Question 2

What is viscosity?

Answer 2

The resistance to flow of a fluid

Question 3

What does viscosity depend on?

Answer 3

Silica content, temperature, and volatiles

Question 4

How does high temperatures affect viscosity?

Answer 4

They make viscosity lower

Question 5

How does low temperatures affect viscosity?

Answer 5

They make viscosity higher

Question 6

How does lower volatiles affect viscosity?

Answer 6

They make viscosity lower

Question 7

How does higher volatiles affect viscosity?

Answer 7

They make viscosity higher

Question 8

What are the types of volcanoes?

Answer 8

Shield volcanoes, stratovolcanoes (composite volcanoes), lava domes, cinder cones (scoria cones), caldera.

Question 9

What are some primary effects in volcano hazards?

Answer 9

• Lava flows
• Pyroclastic Activity
• Release of gases

Question 10

What are some secondary effects in volcano hazards?

Answer 10

• Debris flows
• Mud flow/ lahars
• Debris Avalanches
• Floods
• Fires

Question 11

What is pyroclastic activity?

Answer 11

A mixture of rock, ash, and gas that travels quickly.

Question 12

Which one is more dangerous, pyroclastic activity or lava flow?

Answer 12

Pyroclastic activity because they spread around faster and farther, and because they are ejected more suddenly.

Question 13

What is a caldera?

Answer 13

A gigantic volcanic depression

Question 14

What are stratovolcanoes?

Answer 14

Large, cone-shaped volcanoes with steeper slopes

Question 15

Magma may erupt along a linear tear called

Answer 15

Fissure

Question 16

What is Lahars?

Answer 16

Mudflows that result when water moves ash

Question 17

What are some warning signs that can indicate that an eruption is imminent?

Answer 17

Tremors
Heat flow
Changes in shape
Emission increases

Question 18

What are hotspots?

Answer 18

A large plume of hot mantle material rising from the Earth

Question 19

What is mass movement?

Answer 19

When the force of gravity causes rocks and soils to move downslope

Question 20

What is a landslide?

Answer 20

Sudden event in which large quantities of rock and soil plunge down steep slopes.

Question 21

What are the different types of motion?

Answer 21

Fall, slide, and flow

Question 22

What does water saturation reduce?

Answer 22

Friction

Question 23

What are the two types of slides?

Answer 23

Rotational slides and translational slides

Question 24

Where does earthflow usually occur?

Answer 24

Occurs on hillsides in humid areas during times of heavy
precipitation or snowmelt

Question 25

What is creep?

Answer 25

Gradual downhill movement of soil and regolith. Very slow process

Question 26

What is solifluction?

Answer 26

Slow, downslope flow of water-saturated materials common
to permafrost areas

Question 27

What are submarine slumps?

Answer 27

Semi coherent blocks break and slip along failure planes.

Question 28

What are submarine debris flow?

Answer 28

Broken material moves as a
slurry of mud with larger clasts.

Question 29

What two positive effects does revegetation have?

Answer 29

It removes water by evapotranspiration and the roots help to bind and anchor regolith.

Question 30

What is regrading?

Answer 30

Redistributing a slope by terracing removes some of the mass loading and catches debris.

Question 31

What is a slump?

Answer 31

Downward sliding of a mass of rock or unconsolidated
material moving as a unit along a curved surface

Question 32

What is undercutting?

Answer 32

A variety of remedial steps can stabilize unstable ground.

Question 33

What is debris flow composed of?

Answer 33

It is composed of volcanic
materials on the flanks of
volcanoes