Volcanic Hazards

Question 1

Lava can flow quickly or slowly depending on its ______.

Answer 1

Viscosity

Question 2

What are lahars?

Answer 2

• Mudflows
• Can be caused my multiple factors- usually from melting ice at high latitiudes.

Question 3

How do glacial floods occur?

Answer 3

Magma causes temperatures to increase, causing glaciers or ice sheets to quickly melt, causing a large amount of water to be discharged

Question 4

What is tephra?

Answer 4

Any type of rock that is ejected by a volcano.

Question 5

What is a pyroclastic flow/Nuees ardentes?

Answer 5

Clouds of burning hot ash and gas that collapses down a volcano at high speeds.

Question 6

What is the spacial distribution for volacnoes?

Answer 6

Occur along divergent and convergent plate boundaries, and at hotspots.

Question 7

What is the ring of fire?

Answer 7

An area of high volcanic and earthquake activity.

Question 8

How is vulcanity measured?

Answer 8

• Using the Volcanic Explosivity Index (VEI)
• Considers factors such as the amount of tephra produced, how high the tephra is ejected, how long the eruption lasts,.

Question 9

What are the characteristics of an effusive volcano?

Answer 9

• Calmer, lower magnitude eruptions
• Lower eruption frequency

Question 10

What are the characteristics of an explosive volcano?

Answer 10

• Intense, higher magnitude eruptions
• Higher eruption frequency

Question 11

How can we prevent volcanic eruptions?

Answer 11

• Volcanic eruptions cannot be prevented.
• Only the risk to people can be prevented e.g. preventing urban planning near volcanoes

Question 12

How can we be prepared for volcanic eruptions?

Answer 12

• Monitoring increases the notice of volcanic eruptions, meaning warnings can be given out.
• Education of volcanoes in the the local area so people know what to do in the case of an eruption.
• Evacuation procedures planned.
• Training response teams.

Question 13

How can we mitigate volcanic eruptions?

Answer 13

• Direct intervention to the volcano e.g. using concrete blocks to prevent lava entering high-risk areas.
• Strengthening buildings that are at a high risk of being impacted by mudflows or ash pileup.
• Create evacuation zones.
• Mitigating the effect on health by having emergency medical aid and rescue.

Question 14

How can we adapt to volcanic eruptions?

Answer 14

• Move away from areas at risk.
• Capitalise on opportunities, such as encouraging tourism.

Question 15

Outline shield volcanoes:

Answer 15

• Wide, gentle slopes
• Basaltic lava
• Frequent, mild eruptions

Question 16

Outline composite volcanoes:

Answer 16

• Steep, made from hardened lava
• Viscious lava
• Explosive, dangerous eruptions

Question 17

Outline Calderas volcanoes:

Answer 17

• Large depression formed after a massive eruption and collapse.
• Infrequent and catastrophic
• E.g. Yellowstone