Mt Etna a level presentation case study

1. Mount Etna - Italy

2. Europe’s highest and most active
volcano.
• Towering above the city of Catania on the island
of Sicily, it has been growing for about 500,000
years and is in the midst of a series of eruptions
that began in 2001.
• It has experienced a variety of eruption styles,
including violent explosions and voluminous lava
flows.
• More than 25% of Sicily’s population lives on
Etna’s slopes, and it is the main source of
income for the island, both from agriculture (due
to its rich volcanic soil) and tourism.

4. Mount Etna: Eruption History
• Etna’s eruptions have
been documented since
1500 BC, when eruptions
forced people living in the
east to migrate to western
Sicily.
• The volcano has
experienced more than
200 eruptions since then,
although most are
moderately small.

5. 1669
• Etna’s most powerful recorded eruption was in 1669,
when explosions destroyed part of the summit and lava
flows from a fissure on the volcano’s flank reached the
sea and the town of Catania, more than ten miles away.
• This eruption was also notable as one of the first
attempts to control the path of flowing lava.
• The Catanian townspeople dug a channel that drained
lava away from their homes, but when the diverted lava
threatened the village of Paterno, the inhabitants of that
community drove away the Catanians and forced them
to abandon their efforts.

6. 1775
• An eruption in 1775 produced large lahars
when hot material melted snow and ice on
the summit, and an extremely violent
eruption in 1852 produced more than 2
billion cubic feet of lava and covered more
than three square miles of the volcano’s
flanks in lava flows.

7. Today
• Etna’s longest eruption began in 1979 and
went on for thirteen years; its latest
eruption began in March 2007, and is still
ongoing.

8. October 30,2002
• An oblique photograph of Mount Etna looking to
the southeast taken by astronauts onboard the
International Space Station on October 30,2002.
• The dark plume rising from the top of the
volcano is an ash cloud.
• The broad white cloud streaming from areas of
lower elevation is smoke produced by forest fires
ignited as a hot lava flow moved through a pine
forest.
• The ash and smoke caused air traffic to be
diverted and forced the closing of roads, schools
and businesses

10. Another view
• An oblique photograph of Mount Etna on the
west coast of the island of Sicily.
• This photo is looking to the southeast with the
Mediterranean Sea in the background and was
taken by astronauts onboard the International
Space Station on October 30,2002.
• The scene shows the ash plume from the
eruption being carried by wind across the
Mediterranean Sea to Libya, over 350 miles
away

12. • Mount Etna consists of two elements
• An ancient shield volcano at its base,
• A younger stratovolcano, which was built on top of the shield.
• The volcano’s slopes currently host several large calderas which
formed when the roofs of magma chambers collapsed inward.
• Etna’s current activity consists of continuous summit degassing,
explosive Strombolian eruptions, and frequent basaltic lava flows.
• Ash clouds from the explosive eruptions are especially hazardous to
aircraft, since ash that is pulled into a jet engine can melt, coat
moving parts with a layer of glass, and cause the engine to shut
down.
• These dangerous ash clouds are often visible from space.

13. Damage
• Etna has also produced
pyroclastic flows, ash falls, and
mudflows, but the lava flows are
the most immediately hazardous
type of activity, especially to the
city of Catania.
• While the flows themselves
usually do not move fast enough
to threaten humans, they can
cover large areas and destroy
crops and buildings.
• In the event of a large flank
(fissure) eruption, evacuating the
inhabitants of towns and cities
near the volcano would be a huge
challenge.

14. Communications
• Etna eruptions are
frequently
accompanied by
minor earthquakes.
• Earthquake damage
caused by tremors
accompanying the
Nov.2002 eruption

15. “Operation Volcano Buster”
• There have been two attempts to control the path of lava
flows threatening to destroy the town of Catania.
• The first was in 1669, and the second was in 1992.
During the 1992 attempt, the United States Marines
worked with Italian volcanologists to develop “Operation
Volcano Buster”, in which they used explosives to blast a
hole in a lava tunnel on Etna’s flank and then dropped
large blocks of concrete into the hole to try and stem the
flow of the lava.
• Like the 1669 attempt, however, this plan was ultimately
unsuccessful.

17. Human-made diversion of lava
flows at Mt Etna in 1992.
During the 1992 eruption of Etna earthworks are used to
save the town of Zafferana Etnea from lava flows.
• In January 1992 an earth barrier 234 m long and 21 m
high was constructed.
• The embankment contained lava for about a month and
was overflowed on 9th April 1992.
• Three additional smaller earthen barriers (length: 90-160
m; height: 6-12 m ) were built in April to gain time while
the lava front was descending towards Zafferana from
the overflowed first embankment.
• .

19. • The main intervention point was located in Valle del
Bove at an elevation of 2000 m, at 8 km from Zafferana.
• Initial interventions called for attempts at plugging a
tunnel by dumping into it linked concrete blocks,
hedgehogs and blasted portions of the solid levee.
• Each intervention caused the partial obstruction of the
tunneled channel, which determined major increases of
lava overflow in Valle del Bove and the consequent halt
of the most advanced fronts.
• The intervention gave at the most two weeks of respite,
before new lava fronts approached the outskirts of
Zafferana.

20. • The final successful intervention was carried out
on May 27-29, 1992.
• An artificial channel was dug departing from the
natural one.
• The solid separation levee was thinned to 3 m
and blasted by 7000 kg of explosives.
• After the explosion, 2/3 of the lava flowed
spontaneously in the artificial channel.
• As a consequence of the intervention the active
natural lava front, that on May 27 was only 850
m from Zafferana stopped

22. March 2000,
• Volcanologists have witnessed dramatic
rings of steam and gas being blown out of
volcanic vents on the side of mighty Mount
Etna in Sicily.