Volcanoes

Question 1

Where are volcanoes found?

Answer 1

Volcanoes are distributed around unstable boundaries of tectonic plates. They are also found on the coast due to the subduction of plate boundaries.

Question 2

What is a volcano?

Answer 2

A volcano is an opening or a crack in the lithosphere where magma from inside the Earth escapes onto the surface.

Question 3

What is a composite volcano? (5)

Answer 3

A composite volcano is tall, symetrically shaped with steep sides and rises up quite high -so lava solidifies before it gets far.

Violent eruptions

Longer periods between eruptions

Located on convergent plate boundaries

Acidic lava, sticky

Question 4

What is a shield volcano? (5)

Answer 4

Produces runny, non acidic lava

Less violent

Shorter periods between eruption

Found on divergent plate boundaries

Gentle sides as lava flows for long distances until it solidifies

Question 5

How can you predict a volcano?

Answer 5

Following:

• Seismic graphs
  -Tiltmetres
  -Temperatue of the volcano and surrounding it
  -Gas levels
  -Water tests: PH, temperature, colours
  -Thermal imaging
  -Changes in shapes of volcano

Question 6

How many people died in the eruption of Mt Etna?

Answer 6

77

Question 7

How many people died in the eruption of Mt St Helens?

Answer 7

57

Question 8

How many died in the eruption of Mt Pinatubo?

Answer 8

847

Question 9

Why do people live near volcanoes?

Answer 9

• Geothermal energy can be harnessed from the steam under the ground so cheaper electricity for locals
• Creates a tourism industry.
• The soil around the volcanoes is rich in minerals and nutrients and therefore creates a great place for agriculture.

Question 10

Volcanoes form along two types of plate boundaries, what are these?

Answer 10

Divergent and convergent plate boundaries.

Question 11

What happens when a volcano forms along a divergent plate boundary?

Answer 11

Two tectonic plates move away from eachother, magma rises up to fill the gap in between.

Question 12

What happens when a volcano forms along a convergent plate boundary?

Answer 12

Two plates move towards eachother.
The oceanic crust between them sinks beneath the continental crust at a subduction zone.
As the oceanic crust sinks into the mantle it creates magma.
This then rises to make an explosive volcano.

Question 13

Eruption of Mount Etna?

Answer 13

• Sicily, Italy
• Composite volcano
• Shape of volcano changed
• Ash explosions at summit

Question 14

Eruption of Mount St Helens?

Answer 14

• Washington, America
• 1980
• Scientists recorded 100s of small earthquakes coming from the mountain.
• Many small eruptions of steam and ash.
• Landslides, lateral blasts and pyroclastic flows.
• Lies on a destructive plate boundary

Question 15

Impacts of the eruption of Mount Helens?

Answer 15

• All animal and plant life within 20km were killed
• Many mud flows meaning the area was covered in debris
• Buildings and bridges destroyed by mudflows

Question 16

Eruption of Mount Pinatubo?

Answer 16

• Philipines
• 1991
• A huge cloud of volcanic ash and gas rises above the mountain.
• Three days later the volcano erupted causing the world’s second largest volcaniv eruption.
• Convergent plate boundary

Question 17

Impacts of the eruption of Mount pinatubo?

Answer 17

• Buildings damaged
• Agricultural impacts
• Economic cost

Question 18

Plan and prep for Mount Helens?

Answer 18

• Monitoring volcano; temp etc
• Roadblocks closing the base of the mountain
• Declaring a state of emergency
• Established a Red zone to warn people.

Question 19

Plan and prep for Mount Pinatubo?

Answer 19

• Early warning systems
• Evacuation
• International assistance

Question 20

Plan and prep for Mount Etna?

Answer 20

• Emergency response systems
• Monitoring volcano
• Evacuation routes