Volcanoes

Question 1

What is a volcano

Answer 1

When molten rock escapes onto the earth’s surface

Question 2

Composite volcano

Answer 2

• Conduit system carries lava
• Lava can break through the walls/fissures

↳ can grow to 1000s of metres high

• Explode violently

Question 3

Shield volcano

Answer 3

• Looks like a shield from above (large+wide)
• Lava is thin and travels far
• Not violent but many explosions

Question 4

Caldera volcano

Answer 4

• Top of last volcano was blown off
• Huge mamga chamber
• Destructive margin volcano

↳ oceanic under continental

Question 5

What happens when a volcano erupts?

Answer 5

Magma rises (in magma chamber) → main vent/secondary cone → out of crater → smoke, ash and dust

crater + blocked with cooled magma = lava bomb

Question 6

Why does a volcano erupt?

Answer 6

• HIgh pressure
• Weaknesses in rock

Question 7

How can you monitor a volcano?

Answer 7

• Digital cameras → photograph safely
• Robot ‘spiders’ → instead of humans
• Satellite images → change in temperature

Question 8

How can you predict a volcano’s eruption?

Answer 8

• Seismometers → magma rising, sulphur levels
• Lasers → detect swelling in volcano
• Ultra sound → low frequency waves in magma

↳ gas + molten rock surge

Question 9

Dangers of a volcano

Answer 9

• Ash fall → very fine, suspends ⇒suffocation
• Pyroclastic falls → hot, solid material
• Mudflow (lahars) → mix of ash + water ⇒ washes things away

Question 10

Advantages of a volcano

Answer 10

• Rich, thick soil → fertile, ⇒ high crop yield
• Attracts tourists → creates jobs ⇒ employment, wealth
• Heat → source of energy

Question 11

Location and date of volcano

Answer 11

• Mount St. Helens (MEDC)
• 20^th March 1980
• America, North State

Question 12

Causes of volcano

Answer 12

• 2 plates colliding to form a destructuve margin

↳ Juna de Fuca and North American Plate

Question 13

Effects of volcano

Answer 13

• Around 57 deaths
• Dozen bridges destroyed
• Covered 230² miles
• Many trees uprooted and washed down river
• Earthquakes

Question 14

Short term responses for volcano

Answer 14

• 24 hour aerial surveillance
• Helicopter search and rescue
• Masks
• Emergency treatment
• Ash cleared from roads

Question 15

Long term responses for volcano

Answer 15

• Trees replanted
• Buildings and roads rebuilt
• Drainage recovered