Mount Etna eruption

Question 1

Facts

Answer 1

• Europe’s highest volcano (3310m)

- Supports rich agricultural land, where 25% of Sicily’s population live on the slopes

Question 2

Causes:

Answer 2

• The volcano lies on a subduction zone where the African plate is being subducted under the Eurasian plate
• Deformation of the plates associated with subduction melts rock which rises through cracks

Question 3

Nature of the volcano:

Answer 3

-Etna has been volcanic for a long time
The fertile soil surrounding the volcano supports agriculture: vineyards and orchards which spread across the lower slopes of the mountain
-Eruptions can be very minor to very explosive
-Normally erupts basaltic lava which is of low viscosity and can travel great distances
-Fissures open up releasing lava flows from many places
-Composite stratovolcano

Question 4

Other hazards:

Answer 4

• Seismic activity
• Gas plumes/ volcanic dust/ ashfalls
• Volcano collapses - huge avalanche of volcanic debris
• Phreatic eruptions - steam driven eruptions that occur when water is heated from beneath the ground generating an explosion of steam, water and ash/ lava bombs

Question 5

Impacts:

Answer 5

• Holiday villas damaged -took lava two weeks to reach the tourist centre of Rifugio Sapienza
• Towns and villages destroyed
• No deaths
• When people do die it is normally when tourists go into dangerous areas - 9 in 1979 and 2 in 1987
• Last 20 years all deaths have been because of lightning strikes and accidents
• Lava destroyed the springs in Zafferana which is the supply of water and has a population of 8,000 people
• Farmland lost - blamed the government for not acting quick enough
• Vineyards destroyed in Zafferana
• Roads destroyed
• Ski areas ruined - tourists stayed away due to safety concerns
• Farms destroyed and covered in ash
• Airport forced to close due to ash on the runway
• Vegetation destroyed
• Animals killed/ habitats destroyed
• More fertile soil - main source of income in the region

Question 6

Management:

Short term:

Answer 6

-The Italian government pledged immediate financial assistance of more than $8 million and tax breaks for villagers
-In 1991-1993 it was attempted to stall the lava flow by constructing earth barriers which proved unsuccessful - barrier was 400 meters long and 20 meters high - contained lava for 3 months before overflowing
To break up an efficient lava tube explosives were detonated near the source
-The main explosion destroyed the lava tube and forced the lava into a new artificial channel
-Dams of soil and volcanic rock put up to protect a tourist spot in Rifugio Sapienza helped to divert the lava flow - none of the towns were damaged but there were losses in agriculture and tourism
-Airport was shut on 29th July

Question 7

Long term:

Answer 7

• People have to rebuild their homes from materials found
• More planning of emergency services and evacuation plans
• Institute of volcanology in Sicily (INGV) has improved methods of monitoring since 1992 by measuring radon gas to detect lava movements within the volcano and GPS to detect changes in the slope angle
• Seismometers