Volcano Test

Question 1

What are the 5 types of Tephra(pyroclastics)

Answer 1

Ash
cinders, 
lapilli, 
bombs
blocks

Question 2

What are the 3 gases that come from volcanoes

Answer 2

Water vapor (70-90%)
Carbon dioxide
Sulfur (stinks)

Question 3

What are the 3 types of lave

Answer 3

Pahoehoe
AA
Pillow

Question 4

Sizes if tephra small to big

Answer 4

Ash - less than 2mm like dust

Bombs - up to 1 meter across, ejected as liquid but hardens in the air

Blocks - can weigh several tons and is the largest

Question 5

Pahoehoe lava traits

Answer 5

• Highly fluid/moves quick
• Congealed skin molds into billowing or ropy looking surfaces
• Very hot
• low viscosity

Question 6

AA Lava

Answer 6

Rough and jagged blocks

Thick lavas press forward with a brittle crust

Cool temps

Question 7

Pillow lava

Answer 7

Rounded like a pillow with a hard crust

Cooled underwater

Question 8

What does a higher gas content in lave mean?

Answer 8

It’s more explosive

Question 9

What are the 3 types of volcanoes

Answer 9

Shield, Composite, Cinder Cones

Question 10

What is viscosity

Answer 10

Resistance to flow. Something that is less fluid and slow has a high viscosity. Something smooth and fluid has a low viscosity

Question 11

How is viscosity affected

Answer 11

Temperature and composition

Question 12

What is the composition of a volcanoes

Answer 12

Silica content , Felsic or mafic

Question 13

How does temperature affect the viscosity of a volcanoes

Answer 13

Higher temps are less viscous meaning they flow faster and more fluid

Question 14

How does silica affect a volcanoes viscosity

Answer 14

Felsic - high silica and high viscosity (it stiffer and less fluid)

Mafic - low silica and low viscosity

Question 15

Is Felsic high or low silica

Answer 15

High

Question 16

Is mafic high or low silica

Answer 16

Low

Question 17

What controls the shape of a volcanoe

Answer 17

Composition of the volcano and temperature

Question 18

Characteristics of a Shield Volcano

Answer 18

Broad, flat slope
Layered lava / quiet eruption
Basaltic (mafic) magma 
Low viscosity 
Mount Kea Hawaii and Belknap in the cascades

Question 19

Characteristics of Cinder Cone volcano

Answer 19

Felsic with high gas content 
High viscosity 
Small with a steep side 
Lava butte in Oregon 
Made of layered tephra 
Explosive w/tephra ejected to make a cone shape

Question 20

Characteristics of a composite volcano

Answer 20

These make up the largest percent of the earths volcanos (60
Percent)
andestic magma , medium to high viscosity
Large 20,000 feet high
Mt Hood
Alternative layers of lava and tephra. Can be quiet and very explosive

Question 21

What are tools a scientist uses to predict or forecast volcanic eruptions

Answer 21

Seismic (earthquake activity)
Increased gas (CO2 and sulfur)
Deformation - physical changes like buldging
Increased snow melt(heat) 
Rock analysis

Question 22

What are cinder come volcanos made up of?

Answer 22

Tephra

Question 23

Is AA lave high or low viscosity

Answer 23

High (moves slow)

Question 24

Is Pahoehoe lava high or low viscosity

Answer 24

Low (it’s fluid)

Question 25

What is crater lake

Answer 25

A caldera

Question 26

What type of lava and magma is underwater

Answer 26

Pillow and Basaltic

Question 27

Is a lava flow a hazard?

Answer 27

Yes it can destroy everything in its path

Question 28

Are tephras a hazards

Answer 28

Yes if people are close to the volcano. Larger blocks and bombs flying out, ash near crops and livestock or ever airplanes

Question 29

What is a Lahar

Answer 29

A volcanic hazard that is a debris flow of mud, rocks and water, this can kill the most people and is the Most dangerous

Question 30

What are lava domes

Answer 30

Volcano hazard Created when very viscous magma builds up and creates and unstable slope

Question 31

What is a pyroclastic flow

Answer 31

High speed avalanche of gas, rock and hot ash during and eruption or when a lava dome collapses

Question 32

Are gases a volcanic hazard

Answer 32

Yes carbon dioxide and sulfur are dangerous . Carbon dioxide can suffocate humans and animals, sulfur can create acid rain and is an ozone destroyer

Question 33

How does viscosity affect gas content

Answer 33

High viscosity traps gas and is explosive and low viscosity releases gas and it a mellow eruption

Question 34

How was crater lake formed

Answer 34

It’s a caldera and was formed when a Mount Manama volcano erupts and there is an empty space in the magma chamber and the volcanic cone collapses leaving a crater

Question 35

What is a crater

Answer 35

Smaller than a caldera

Question 36

What is a Felsic eruption

Answer 36

High silica , high viscosity, lots of trapped gas and very explosive

Question 37

What is a mafic eruption

Answer 37

Low silica, low viscosity, not a lot of gases and non violent eruption

Question 38

Mount Hood

Answer 38

Last erupted in 1805, eruptions of growth and lava domes, most likely scenarios is the collapse of lava dome near crater rock that would cause pyroclastic flows and lahars

Question 39

Mount Rainier

Answer 39

Most dangerous volcano in cascades , large lahars of ice and snow could kill lots of people in the area

Question 40

South sisters

Answer 40

Last erupted 2,000 years ago, it was bulging at the base but nothing now

Question 41

Mount Bachelor

Answer 41

Poses little threat erupted 8-10,000 years ago