volcanic hazards

Question 1

what is an active volcano

Answer 1

a volcano that erupted in the last 10,000 years

eg: Mount Etna, Italy

Question 2

what is a dormant volcano

Answer 2

a volcano that hasn’t erupted in 10,000 years but is expected to erupt again
eg: Mount Fuji, Japan

Question 3

what is an extinct volcano

Answer 3

a volcano that isn’t expected to erupt again

eg: Castle Rock Edinburgh, Scotland

Question 4

characteristics of volcanoes at constructive margins

Answer 4

• usually shield volcanoes
• produce basaltic lava: dark lave hot (1000 degrees celcius), low viscosity
• frequent weak eruptions
• wide sloped volcano/shield volcanoes
• low gas content
• underwater margins: magma rises to fill spaces left by plates to form ocean ridges
• land margins: form rift valleys that thin out and allow lava to pass through

Question 5

characteristics of volcanoes at destructive margins

Answer 5

• usually composite volcanoes
• produce andesitic and rhyolitic lava : cooler with higher viscosity
• infrequent violent eruptions
• steep volcanoes
• high gas content

Question 6

name 6 volcano hazards

Answer 6

• pyroclastic flows: mix of super heated gas, ash and volcanic rock that travel far (10km-15km) at high speeds(80 km/h) and destroy everything in their path
  temperature: 800 degrees Celsius Pompeii
• lava flows: speed depends on volcano slope and lava viscosity. typically lava flows are slow but destroy anything in their path
• volcanic gases: carbon dioxide/sulphur dioxide released by lava that make it difficult to breathe
• tephra(pyroclastic and ash fall out): material that is ejected from the volcano and falls to the ground. ranges in size that can damage/kill or make it hard to breathe

lahars(mudflows): occur when tephra mixes with large bodies of water - 1985 Amero Tragedy

acid rain: volcanic gases react with water vapour which damages ecosystems
acidity of 4

Question 7

how is the magnitude of volcanic hazards measured

Answer 7

measured using the Volcanic Explosivity Index which grades volcanoes on a scale of 0-8 based on the amount and height of material ejected.

-Eyjafjallajokull was a 3
-Mnt St Helens was a 5
Hawain volcanoes are 1
-Yellow Stone was 10

Question 8

what is the importance of the frequency of volcanic events

Answer 8

typically volcanoes with less frequent volcanic eruptions are larger in magnitude

Question 9

randomness vs regularity of volcanic events

Answer 9

some volcanoes will erupt at regular intervals while others may be dormant for a long time and then erupt several times

estimated that 50 to 60 volcanoes erupt per year

Question 10

predictability of volcanic events

Answer 10

• shape, ground deformation monitored with lasers and tiltmeters
• small earthquakes show movement in magma
• Sulphur in the air can be measured with gas spectrometers

Question 11

short term responses

Answer 11

occur immediately after the event like

evacuations and emergency supplies

Question 12

volcano case study :

location
date
plate margin
volcano type

Answer 12

• Iceland Eyjafjallajökull
• 20th March 2010
• constructive north American and Eurasian plate
• composite volcano

Question 13

4 economic impacts of the Eyjafjallajökull volcano eruptions

Answer 13

• airlines lost £130 million per day
• European tourism lost between £5-£6 million
• £80 million loss for Iceland
• Nissan halted production as parts couldn’t be imported from Iceland- globalization/TNC

Question 14

3 social impacts of the Eyjafjallajökull volcano eruptions

Answer 14

• 0 deaths: volcano erupted 75 miles from capitol
• people had to wear goggles and masks due to the thickness of ash
• flights were delayed and cancelled

Question 15

4 environmental impacts of the Eyjafjallajökull volcano eruptions

Answer 15

• temperature rises killed fish
• lava and ash rich soils are good for agricultural use
• eruption caused ice on volcano to melt which caused floods in southern Iceland on the 14th of April
• plankton bloom triggered by dissolved iron deposited by volcano

Question 16

5 immediate responses to the Eyjafjallajökull volcano

Answer 16

• 500 cattle farmers were evacuated
• roads shut down
• flights cancelled
• local population was evacuated for safety and because of respiratory threats due to the ash
• authorities to order 700 people to evacuate due to flooding in the south

Question 17

5 long term responses to the Eyjafjallajökull volcano

Answer 17

• jewellery created from ash to sell to tourists
• roads reconstructed
• volcano made into a tourist attraction
• rocks from volcano used for construction
• residents clean up ash

Question 18

how was Iceland vulnerable to the Eyjafjallajökull volcano - 3

Answer 18

• vulnerable to ash clouds is higher due to the extent of the eruptions
• Iceland has a team of scientists and meteorologists dedicated to researching and monitoring volcanic activity at the Icelandic Met Office
• between the 3rd and 5th of May they received multiple warnings about the earthquake

Question 19

what 4 hazards occurred as a result of the Eyjafjallajökull volcano

Answer 19

• on the 20th of March an eruption of lava
• on the 14th of April flooding
• an estimate 140 million cubic meters of ash released
• interaction of water and magma created 10km lava plumes of fine ash and gas
• this was carried south easterly to winds Norway, the Faroe Islands and Northern Scotland

Question 20

volcano management: prevention

Answer 20

• volcanoes cannot be prevented
• the risks of volcanoes can be prevented by keeping people away from volcanic hazards
• e.g. preventing building around volcanoes

Question 21

volcano management: preparedness - 4

Answer 21

• monitoring allows you to notice volcanic eruptions so warnings can be given out
• educating those who lives around volcanoes on the risk so people know what to do if there is an eruption
• planning evacuation procedures
• training response teams

Question 22

volcano management: mitigation - 4

Answer 22

• direct intervention to the volcano: e.g. concrete blocks to steer lava away from areas at risk
• strengthening buildings at risk of mudflows or ash pileup
• evacuation and exclusion zones
• mitigating effects on health by having emergency aid and rescue

Question 23

volcano management: adaption - 3

Answer 23

• move away from areas at risk
• capitalize on opportunities like encouraging tourism
• change profession so you are less likely to be affected by volcanic hazards