Chapter 4

Question 1

What is Volcanism

Answer 1

When magma makes it way to the earth’s surface.

Question 2

Vocanoes

Answer 2

landforms formed by the extrusion of lava or the ejection of rock fragments from a vent.

Question 3

Explosive Eruptions

Answer 3

Also called pyroclastic eruptions long story short they erupt violently.

Question 4

Effusive Eruptions

Answer 4

Eruptions dominated by lava flows.

Question 5

How was the atmosphere created

Answer 5

By degassing magma during the time following Earths formation.

Question 6

What is VEI an acronym for?

Answer 6

Volcanic Explosivity Index

Question 7

viscosity

Answer 7

Does it flow like corn syrup? If yes then it has a high viscosity.

Question 8

what are the three factors in lavas viscosity?

Answer 8

1. The amount of silica it contains. 2. The temperature. 3. The amount of gas dissolved in magma.

Question 9

How silica rich are Felsic rocks?

Answer 9

High usually 65% or more. Examples include rhyolite.

Question 10

How silica rich are Mafic Rocks?

Answer 10

Low usually about 50% Basalt is a common Mafic Rock.

Question 11

How silica rich are Intermediate rocks?

Answer 11

usually between felsic and mafic rocks 50%-65% silica.

Question 12

Vent

Answer 12

The opening through which an eruption takes place

Question 13

Crater

Answer 13

A basinlike depression over a vent at the summit of a volcanic cone. Material is not always ejected from the central vent.

Question 14

What is a flank eruption?

Answer 14

Lava pours from a vent on the side of a volcano.

Question 15

What are Effusive Eruptions classified by?

Answer 15

The lava flow.

Question 16

pahoehoe

Answer 16

The skin cools on lava and it looks ropy or billowy surface. Kind of like fat roles think jabba the hutt.

Question 17

spatter cone

Answer 17

a small steep sided cone built from lava sputtering out of a vent.

Question 18

What is a Lava Tube?

Answer 18

A tunnel like conduit for lava to flow.

Question 19

Flood basalts

Answer 19

A vast outpouring of lava over a large area with multiple lava flows. It kind of looks like a wetland for lava.

Question 20

Columnar Jointing

Answer 20

Volcanic rocks in parallel, usually vertical columns, mostly six-sided; also called columnar structure.

Question 21

Pillow structure

Answer 21

Pillow structure is formed when lava erupts into water.

Question 22

Pyroclastic Flow

Answer 22

A mixture of gas and pyroclastic debris that is so dense that it hugs the ground as it flows rapidly in low areas. Think of a flash flood.

Question 23

what are the 3 different types of volcanoes?

Answer 23

1. Shield 2. Cinder Cone 3. composite.

Question 24

How are Shield Volcanoes constructed?

Answer 24

Broad, gently sloping cone constructed of solidified lava flows. Think of captain Americas shield.

Question 25

What is a Cinder Cone constructed of?

Answer 25

A volcano constructed of pyroclastic fragments ejected from a central vent. commonly have a slope of about 30 degrees. also known as pumice cones.

Question 26

Composite Volcano

Answer 26

Constructed of Alternating layers of pyroclast and lava flow.

Question 27

Circum-Pacific belt

Answer 27

Major belt around the edge of the pacific ocean on which most composite volcanoes are located and where many earthquakes occur.

Question 28

What are Lava Domes.

Answer 28

steep-sided dome-or spine-shaped mass of volcanic rock. Usually formed from highly viscous lava that does not flow very far before it solidifies.

Question 29

What is a Caldera?

Answer 29

A volcanic depression much larger tan the original crater having a diameter of at least 1 kilometer. Crater Lake is an example of this.

Question 30

What is midigation

Answer 30

Reducing the impact of volcanic eruptions.

Question 31

What likely killed the people in Pompeii

Answer 31

Hot pryloclasts.

Question 32

Lahars

Answer 32

Really intense flash floods, but like on the river scale.

Question 33

Active volcanoe

Answer 33

A volcano that is either currently erupting or has erupted recently.

Question 34

Dormant or extinct volcanoes.

Answer 34

Volcanoes that have not erupted in a very long time.

Question 35

What is the earliest notifying feature that a volcano is going to explode?

Answer 35

Increased seismic activity.

Question 36

What are the only conditions that mantle rocks melt?

Answer 36

Decompression melting and flux melting.

Question 37

convergent boundaries and volcanoes

Answer 37

Traditionally the volcanoes are composite in construction and the most known volcanoes are composite.

Question 38

Where do volcanoes that form away from plate boundaries form from?

Answer 38

Hot spots or plums from the earth's core.

Question 39

What are the three most deadly volcanic hazards?

Answer 39

1. Tsunami 2.Pyroclastic Flows 3.Famine and other indirect effects.

Question 40

What are the three components of lava?

Answer 40

1. Crystals 2.Molten silicate rock 3.Gases