Volcano deck (Exam 2)

Question 1

What is a volcano?

Answer 1

An erupting vent through which molten rock surfaces or a mountain built from magmatic eruptions.

Question 2

What is a volcano usually the result of?

Answer 2

Tectonic activity

Question 3

What are the 4 eruption types of a volcano?

Answer 3

Lava flows, pyroclastic debris, pyroclastic flows, gases

Question 4

What are the different types of lava flows?

Answer 4

Rhyolitic lava flows, andesitic lava flows, basaltic lava flows and mafic/basaltic

Question 5

Why don’t all lava flows appear the same?

Answer 5

Viscosity

Question 6

Describe rhyolitic flows:

Answer 6

it’s high in viscosity and it cools significantly slow (600-700 C)

Question 7

Describe andesitic flows:

Answer 7

it’s moderate in viscosity and it cools moderately (700-1000 C)

Question 8

Describe basaltic flows:

Answer 8

it’s low in viscosity and it’s cools between 1000-2000 C)

Question 9

What is a pyroclastic flow?

Answer 9

A fast moving avalanche that occurs when hot volcanic ash and pyroclastic debris mix with air

Question 10

What is pyroclastic debris?

Answer 10

unconsolidated fragment resulting from an eruption

Question 11

What is volcanic gas?

Answer 11

are water vapor (H2O), carbon dioxide (CO2), and sulfur dioxide (SO2).

Question 12

What are lahars?

Answer 12

volcanic mudflows where ash and debris mix with water and rush down the flank of a volcano.

Question 13

Volcanic architecture terms:

Answer 13

Magma chamber, Fissure, Crater, Caldera

Question 14

Define magma chamber:

Answer 14

a large, irregularly shaped space below ground filled with magma

Question 15

Define Fissure:

Answer 15

a conduit in a magma chamber in the shape of a long crack through which manga rises and erupts at the surface

Question 16

Define Crater:

Answer 16

a bowl-shaped depression at the top of a volcano, formed as erupted lava piles up around the vent

Question 17

Define caldera:

Answer 17

a gigantic volcanic depression when the magma chamber empties and the volcano collapses in

Question 18

Shield volcanoes are?

Answer 18

Considered the largest and are associated with basaltic lava flows, which are effusive.

Question 19

Cinder cone volcanoes are?

Answer 19

conical piles of pyroclastic debris, very small, symmetrical.

Question 20

Stratovolcanoes are?

Answer 20

large and cone-shaped, composed of alternating layers of lava and pyroclastic debris; these volcanoes are associated with rhyolitic lavas, which are explosive.

Question 21

Eruption styles:

Answer 21

Strombolian, Vulcanian, plinian

Question 22

What are strombolian eruptions?

Answer 22

Regular explosions of intermediate magma, mildly explosive

Question 23

What are Vulcanian eruptions?

Answer 23

Explosive intermediate-felsic magma and can eject material 3-10 km in the atmosphere

Question 24

What are plinian eruptions?

Answer 24

The largest of the three and eject a LARGE quantity of material (think Mt st helens, Pinatubo, etc.)

Question 25

What are the magma generations?

Answer 25

Flux Melting-Subduction Zone, Decompression Melting-Divergent Boundary

Question 26

How do Flux-melting subduction zones work?

Answer 26

magma is generated as the subducting plate melts as it approaches the mantle, the lower plate releases water and volatiles which cause melting of the mantle above the subducting plate

Question 27

How do decompression melting divergent boundary work?

Answer 27

As the material from the mantle rises, pressure decreases lowering the melting point, allowing the mantle to melt into magma (it was previously solid due to high pressure)