Chapter 5 Volcano Test

Question 1

Convergent Plate Boundaries

Answer 1

Clashing together (subduction zones)

Question 2

Divergent Plate Boundaries

Answer 2

Pulling Apart (Mid-ocean ridges)

Question 3

Hot Spots

Answer 3

Where mantle plumes cut the lithosphere

Question 4

What are signs that scientists look for when predicting volcanic eruptions?

Answer 4

Earthquake activity - magma flow increases seismicity.

Heat flow - magma causes volcanoes to “heat up.”

Changes in shape - magma causes expansion.

Emission increases - changes in gas mix and volume.

Question 5

What happened to the surrounding area around Lake Nyos in Cameroon as a result of the eruption there?

Answer 5

belched CO2 during overturn. Moved down the valleys as a heavier-than-air underflow.

Question 6

What is the greatest hazard to humans that is associated with volcanos?

Answer 6

Pyroclastic Debris

Question 7

Iceland is an example of a hot spot located over what?

Answer 7

Mid-Atlantic Ridge

Question 8

Mafic Lava Characteristics

Answer 8

very hot, low silica, and low viscosity

Question 9

Felsic Lava Characteristics

Answer 9

not as hot, high in silica and volatiles, and have a high viscosity.

Question 10

Stratovolcano Volcano

Answer 10

also called composite volcanoes. Large, cone-shaped volcanoes with steeper slopes. Made of alternating layers of lava, tephra, and debris. Examples include Mount Fuji, Mount Rainier, and Mount Vesuvius.

Question 11

Cinder Cone Volavno

Answer 11

( AKA: Scoria cones): Conical piles of tephra; the smallest type of volcano. Built of ejected lapilli and blocks piled up at a vent. Often symmetrical, with a deep summit crater. Typically from a single eruption event.

Question 12

Shield Volcano

Answer 12

Broad, slightly dome-shaped (like an inverted shield). Constructed by lateral flow of low-viscosity basaltic lava. Have a low slope and cover large geographic areas. Mauna Loa in Hawaii is a perfect example.

Question 13

Explain what a caldera is. Know how are they formed?

Answer 13

A caldera is a large crater-shaped basin that forms when the top of a volcano collapses.

Question 14

Lahar

Answer 14

water-rich debris flow of ash and blocks. mudflows result when water moves ash.

Question 15

Pillow basalt (lavas)

Answer 15

round blobs of basalt cooled in water

Question 16

Tuff

Answer 16

lithified ash, may or may not contain lapilli

Question 17

Pele’s Hair

Answer 17

thin glass strands

Question 18

Pele’s Tears

Answer 18

frozen droplets

Question 19

A’a’

Answer 19

Hawaiian word describing basalt that solidifies
with jagged, sharp, angular textures. Forms when hot basalt cools & thickens.

Question 20

Pahoehoe

Answer 20

Hawaiian word describing basalt with a glassy or ropy texture. Forms when extremely hot basalt forms a skin.

Question 21

What is tephra? Be able to identify examples.

Answer 21

deposits of pyroclastic debris of any size. Examples are Ash, Lapilli, Air-fall tuff, and Ignimbrite.

Question 22

What are Volcanic Bombs and how are they formed?

Answer 22

A small lump of magma that is thrown up into the air during an explosive volcanic eruption as molten rock and then cools into a solid fragment before it reaches the ground.

Question 23

What is volcanic debris? List some examples.

Answer 23

wetted debris that moves downhill. Examples are gas, lava, and fragmented debris called tephra.

Question 24

What are common volcanic gasses?

Answer 24

Water (H2O)
Carbon dioxide (CO2)
Sulfur dioxide (SO2)
Hydrogen sulfide (H2S)

Question 25

Compare and contrast effusive and explosive eruptions

Answer 25

Effusive eruptions—An eruption dominated by the outpouring of lava onto the ground. Produce lava flows.

Explosive eruptions—blow up. Have high silica content. Lots of stuff gets erupted in the air. As a result, it changes the climent-adjasent to a subduction zone.

Question 26

What eruption buried the town of Pompeii with pyroclastic debris in 79 A.D.?

Answer 26

the eruption of Mount Vesuvius

Question 27

Dormant Volcanos

Answer 27

hasn’t erupted in hundreds to thousands of years

Question 28

Active Volcanos

Answer 28

erupting, recently erupted or likely to erupt

Question 29

Extinct Volcanos

Answer 29

not capable of erupting

Question 30

Review the table that compares and contrasts Basaltic, Andesitic, and Rhyolitic Lava flows and their locations.

Answer 30

Basaltic Magma: Least (~50%) Silica Content. Least Gas Content. Least viscous. Rarely explosive. Highest Melting Temp. Located on Rifts, oceanic hot spots.

Andesitic Magma: Intermediate (~60%) Silica Content. Intermediate Gas Content. Intermediate Viscosity. Sometimes explosive. Intermediate Melting Temp. Located on Subduction boundaries.

Rhyolitic Magma: Most (~70%) Silica Content. Most Gas Content. Most viscous. Usually explosive. Lowest Melting Temp. Located on Continental hot spots.

Question 31

Review large Igneous Provinces (LIP) - what type of lava are they typically formed from?

Answer 31

LIPs—unusually large outpourings of magma. Mostly mafic, include some felsic examples. Mostly mafic, include some felsic examples. Mantle plume first reaches the base of the lithosphere. Erupts huge volumes of mafic magma as flood basalts.

Question 32

Know how volcanic eruptions can impact glocal temperatures - some even changing global climates for a period of time.

Answer 32

Ash and aerosols (tiny liquid droplets) are injected into the stratosphere, rapidly circling the globe. Particles remain in the stratosphere for months to years. This reflects solar radiation, causing atmospheric cooling.