Volcanic Hazards

Question 1

Constructive margins what lava is formed here, what is it like

What happens if Marvin is under water and on land

Answer 1

Basaltic lava is formed here
Very fit and low viscosity
Frequent eruptions, long time but not violent

If margin underwater, magma rises to fill space by plates moving apart forming ocean ridge

If margin is on land, plates form rift valleys so plates become gunner and magma can break through surface

Question 2

What lavas form at destructive margin

Answer 2

Andesitic and rhyolitic lavas form

Cooler and more viscous so flow less easily
Eruptions occur intermittently and are short lived

Can cause violent eruption at subduction zones by blocking volcanic vents making pressure build up

Question 3

4 primary hazard from volcanoes

Answer 3

Pyroclastic flows
Lava flows
Volcanic gases
Pyroclastic and ash fallout

Question 4

What are pyroclastic flows / nuees Ardentes

Answer 4

Mixture of super heated gases, ash and rock which flows down side of volcano at high speed covering a long distance

Question 5

What are lava flows

Answer 5

lava from a volcanic vent which flows down side of volcanic

Usually slow but depends on steepness of slope and lava viscosity

Question 6

Volcanic gases

Answer 6

Lava contains CO2 and sulphur dioxide which is released into atmosphere

Question 7

Pyroclastic/ Tephra and ash fallout

Answer 7

PF/ tephra - material that has been ejected from volcano and falls back to ground
AF- when most of the material consists of ash

Rock weighing tonnes to tiny ash particles

Question 8

2 secondary hazards

Answer 8

Lahars / Mudflows

Acid rain

Question 9

What are lahars

Answer 9

Volcanic material mixes with late amounts of water so it flows very quickly and much longer distances

Question 10

What is acid rain

Answer 10

Volcanic gases react with water vapour in atmosphere and falls as acid rain

Sulphuric acid formed from sulphur dioxide which damages ecosystems and deteriorates stone and metal

Question 11

How is the magnitude measured

Answer 11

Volcanic explosively index

Scale of 0-8 based on amount of material ejected and how high material reached

Question 12

Social impacts

4

Answer 12

Death
Injury
Homelessness
Social infrastructure destroyed

Question 13

Environmental impacts

4

Answer 13

Ecosystems damaged or destroyed
Acidification by acid rain damages aquatic ecosystems killing some plants and animals and disrupts soil nutrient content
Gases enhance greenhouse effect
Ash coulda reduce sunlight- desecrate earth temp

Question 14

Economic impacts

4

Answer 14

Destroy businesses
Ash clouds prevent aircraft and damage crops - damage economy
Expensive repairs to infrastructure
Boost economy by attracting tourists

Question 15

Political impacts

3

Answer 15

Damage to agricultural land, food shortages,conflict in political interest in food aid

Development slows by investing into repairs

Slow or bad response rioting by locals

Question 16

Presentation against volcanic hazard

Answer 16

Can’t prevent apart from not developing or living near one

Question 17

Preparing

3

Answer 17

Installing monitoring systems to predict eruption then evacuate
Have specific reduce and response teams
Prevent entry into area

Question 18

Adaptation

2

Answer 18

Strengthen buildings to prevent collapse from ash

Use fertile soil for farming or working in tourist industry

Question 19

How they are measured

Answer 19

Volcanic Explosivty index