Tectonics Lesson 7: Volcanic Hazards

Question 1

How many people have died of eruptions in the past 300 years?

Answer 1

260,000

Question 2

Describe lava flows

Answer 2

Primary hazard
Streams of lava that have erupted from the earth’s surface
1170 C
Destroy everything
Move so slowly not hugely life threatening

Question 3

Describe pyroclastic flows

Answer 3

Primary hazard
Dense hot rock, lava, ash, gases ejected
700 C
Move quickly up to 100km per hour
Destroy everything

Question 4

Describe tephra and ash falls

Answer 4

Primary hazards
Tephra are volcanic rock that erupt
Larger pieces fall near the volcano which cause injury
Ash can travel thousands of km, causing poor visibility and slippery roads.
Roofs can collapse under the weight of ash

Question 5

Describe gas eruptions

Answer 5

Primary hazard
Magma contain dissolved gases released into the atmosphere
80% water vapour and CO2 and SO2
Travel thousands of km

Question 6

Describe lahars

Answer 6

Secondary hazard
Masses of rock, mud and water that travel down the sides of volcano
Vary in size and speed, and are too fats to outrun
Eruption melts snow and ice or heavy rainfall has occurred and eroded rocks causing a surge

Question 7

Describe Jokulhlaup

Answer 7

Glacial outburst floods
Heat of volcanoes melts snow and ice causing floods
Large amounts of rock, water, gravel and ice released

Question 8

Can volcanoes be predicted?

Answer 8

Use GPS and radars around volcanoes
Monitor for small earthquakes, changes to the surface of the volcano , changes to the ‘tilt’ of a volcano (moving magma inside can the slope angle).
Not all are accurate

Question 9

Eyjafjallalokull Eruption, Iceland

Answer 9

20th March 2010 lava erupted

14th April eruption beneath the ice cap

Question 10

Impacts of Iceland eruption 2010

Answer 10

Volcanic ash produced over 33,000 feet high which spread over western Europe
Jokulhlaups produced due to meltwater from glacer - surging water of 17 C

Question 11

Social impacts of Iceland Eruption

Answer 11

Ash contaminated water supplies
700 people evacuated due to flooding
Goggles and facemasks had to be worn
10 million passengers unable to board flights

Question 12

Economic impacts of Iceland eruption

Answer 12

100,000 commercial flights cancelled
$1.7 billion lost for airlines
European economy lost $5 billion
Eurostar benefited from an extra 50,000 passengers