Chapter 25. 3

Question 1

What is the boundary that marks a density change between layers ?e

Answer 1

Discontinuity

Question 2

How are discontinuities identified ?

Answer 2

By studying seismic waves

Question 3

What are shadow zones ?

Answer 3

Shadow zones are areas where no seismic waves occur.

Question 4

What is another term for shadow zones ?

Answer 4

Dead zones

Question 5

What are the degree ranges which shadow zones are formed ?

Answer 5

Between 105 and 140 degrees from the epicenter

Question 6

Is the outer core a solid or a liquid ?

Answer 6

Liquid

Question 7

Is the inner core a solid or liquid ? Why?

Answer 7

Solid and it is a solid because of the amount of pressure

Question 8

What makes up the lithosphere ?

Answer 8

Crust and uppermost mantle

Question 9

What is the asthenosphere ?

Answer 9

A plastic like layer which Earth’s plates move

Question 10

Which elements make up mantle ?

Answer 10

Calcium, Aluminum, Iron, and Magnesium

Question 11

What elements make up the core ?

Answer 11

Iron and Nickel

Question 12

Viscosity

Answer 12

The measure of a fluid’s resistance to flow

Question 13

Silica

Answer 13

the chemical compound silicon, SIO subscript two, is a common ingredient in most magma

Question 14

Cinder Cone Volcanoes

Answer 14

Tend to be small in range, have heights in the hundreds of meters range, and have short eruption cycles

Question 15

Composite Volcanoes

Answer 15

large and steep - sided, often thousands of meters high and tens of kilometers across the base, and composed of layers of both lava and ash

Question 16

Shield Volcanoes

Answer 16

broad, flat structures composed of layer upon layer of lave flows

Question 17

Where can melting occur ?

Answer 17

In the asthenosphere

Question 18

Why does magma rise ?

Answer 18

it is less dense than the surrounding rock

Question 19

How does magma rise ?

Answer 19

Magma rises is the pressure conditions allow and there are conduits in the rock

Question 20

Where do volcanic eruptions occur ?

Answer 20

Volcanic eruptions occur where plates separate along a mid oceanic ridge or collide along a subduction zone

Question 21

Where are most of Earth’s volcanoes located ?

Answer 21

They are located along plate boundaries that surround the Pacific Ocean called the Ring of Fire

Question 22

How do volcanoes form ?

Answer 22

Volcanoes form where tectonic plates collide along subduction zones ?
Example :
Volcanoes the northwestern United States and Alaska form along subduction zones within the Ring of Fire.

Question 23

What are hot spots ?

Answer 23

Hot Spots are areas of volcanic activity that where magma moves toward the surface in large, balloon like plumes.

Question 24

Where do Hot Spots originate ?

Answer 24

Scientists believe that these plumes originate near the core-mantle boundary and that they are stationary

Question 25

What are pyroclastic materials ?

Answer 25

Solids that erupt from volcanic eruptions

Question 26

What molten, or liquid, rock stored inside the Earth called

Answer 26

Magma

Question 27

What are two locations where volcanic activity occurs due to divergence ?

Answer 27

East African Rift Valley

Mid - Atlantic Ridge

Question 28

Are Hot Spots stationary ?

Answer 28

Yes

Question 29

What is the smallest pyroclastic material ?

Answer 29

Volcanic Ash

Question 30

What is the largest pyroclastic material ?

Answer 30

Volcanic Blocks and Bombs

Question 31

What are the type of gases that erupt from a volcano ?

Answer 31

Water Vapor
Carbon Dioxide
Sulfur Dioxide

Question 32

How are volcanoes classified ?

Answer 32

According to their size, shape, and the materials that they erupt \

Question 33

What are three types of volcanoes ?

Answer 33

Cinder Cones
Shield
Composite