Volcanoes

Question 1

What is a volcano

Answer 1

A landmass that produces lava, gas, ash or has done so in the past

Question 2

Where do volcanos form

Answer 2

Convergent boundaries, divergent boundaries, and hot spots

Question 3

What happens to the viscosity of the magma as it goes from mafic to felsic and why

Answer 3

As magma becomes more felsic the viscosity increases because there are more covalent bonds causing a greater resistance to flow

Question 4

Does mafic magma or felsic magma have more violent eruptions and why

Answer 4

Felsic has far more violent eruptions because the viscosity doesn’t allow gas to escape slowly, so it can build up lots of gas pressure before finally releasing

Question 5

What are the mafic lava textures and describe each

Answer 5

Aa is a very rough and ragged formation and Pahoehoe is very smooth and shiny surface

Question 6

What are the seven things that are produced by a felsic volcanic eruption

Answer 6

Tephra (fine rock powder that settles, ash, lapilli, volcanic bombs, volcanic block, weld tuff, and pumice

Question 7

What three gasses are most abundantly produced during an eruption

Answer 7

H2O, CO2, and SO2

Question 8

What two groups that classify volcanoes called

Answer 8

Central vent volcanoes and large-scale volcanic terrains

Question 9

What are the types of central vent volcanoes

Answer 9

Shield volcano, stratovolcano, and rhyolite caldera complexes

Question 10

What is common in the composition of magmas found in shield volcanos and how does that affect the structure of the volcano

Answer 10

The magma is low in silica content meaning eruptions are less violent causing broad and gentle slopes down the side of the volcano

Question 11

Is there a common composition of magmas found in stratovolcanoes

Answer 11

No, stratovolcanoes vary from mafic all the way to felsic in their magmas composition but have to have some kind of alternating layer between the different compositions

Question 12

What is common in the composition of magmas found in rhyolite caldera complexes and how does that affect the structure of the volcano

Answer 12

The magma is high in silica contents meaning eruptions are more violent causing the ground to collapse after an eruption because the built-up pressure from the gas is released

Question 13

What do rhyolite caldera complexes look like before and after an eruption

Answer 13

A rhyolite caldera complex often looks like a number of vents at the earth’s surface with no structure around it and after it erupts it seems like an “inverse volcano” because it is sunk into the ground because all the gas and some magma comes out