Etna Case Study

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Mount Etna - Case Study

  • Located on the east coast of Sicily
  • Europe's highest and most active volcano
  • Only around 77 confirmed deaths - past 20 years all accidents or lightning strikes
  • Around 25% of Sicily's population live on its slopes
  • Classified as a Decade Volcano
  • Subject to several caldera collapses and changing eruptive centres
  • At least 60 flank eruptions and many summit eruptions since 1600 - around half since 1900
  • Since 2001, Etna has had an eruption every year
  • Well monitored and actively managed - unlike Chaitén
  • Setting is structurally highly complex - subduction of African plate below Eurasian plate
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Etna - Nature of the Hazard

  • Fertile soils support agriculture on slopes and across Plain of Catania
  • Variety of different eruptions, from minor to majorly explosive
  • Composite volcano erupting basaltic lava with a low viscosity - can therefore travel large distances easily e.g Zafferana 1992 (7km away)
  • Fissures often open up in a variety of locations along with small parasitic cones (hornitos) which spatter lava from the side of the cone
  • Other potential hazards can include:
    • Seismic activity connecting with eruptive activity - 02/03 flanks slipped by up to 2m due to seismic activity causing structural damage
    • Gas plumes, volcanic dust and ash - high magnitude explosive events - creates serious problems to agriculture, settlements and road/air travel
    • Flank collapse before/following - leading to a huge avalanche of volcanic material - once occurred at Valle del Bove
    • Phreatic eruptions - steam driven - occur when water is heated by magma, generating explosions of steam, water, ash blocks and lava bombs
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Etna - Management, Responses and Monitoring

  • Long history means experience with management
  • Little government intervention - 1991-93 Zafferana threatened by lava flow - government made significant intervention - used explosives to destroy lava tubes which had been directing the flow and redirected the lava into artificial tubes which led elsewhere
  • 2002 - soil/volcanic rock dams were put in place to protect tourist resorts - use of Italian Army machinery - tax breaks offered and $8m pledged by government 
  • INGV monitored volcano for 20 years via a permanent network of remote sensors
  • Geochemical monitoring programs test gas emissions - SO2 emissions can help estimate size of magma batches inside the volcano
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