Recent Etna

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Recent Etnas explosive eruptions threaten
seriously aviation in Central Mediterranean
regionMauro ColtelliINGV Catania, Italy
Image courtesy of NASA
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Explosive eruptions occurred in the last 25 years
2001 long-lasting eruption
2002-3 very long-lasting eruption
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Main features of Etnas explosive eruptions

• Short-lasting eruptions
• Duration from minutes to a few hours
• Magnitude from violent strombolian to subplinian
  (from 4 to 15 km high eruptive plumes)
• One plinian eruption in historical time (26 km
  high plume)
• Occurrence more than 150 in the last 25 years
• Frequency up to several tens in a few months
• Long-lasting eruptions
• Duration from days to a few months
• Magnitude violent strombolian (low-troposphere
  plumes)
• Occurrence only two in the last century but at
  least 8 occurred in the last four centuries

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Short-lived eruptive episode 22 July 1998
About 3 min-long event Fallout on 800 km2 on
land Volume 1.3x106 m3 Mass rate 6.7x106 kg
s-1 Column height 12 km
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Eruptive column and tephra dispersal of22 July
1998 eruptive episode
Elutriation of steam and very fine ash from the
column top
isomass contour lines (g/m2)
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Fallout deposit dispersion of the subplinian and
plinian eruptions at Etna
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26 April 2000 an Airbus 320 encountered Etna ash
cloud
Cockpit windows damaged Minor exterior
damages Small/No ingestion of ash into the
engines Emergency landing in a few minutes after
the encounter
Courtesy of Franco Colombo, Italian Air Force
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Long-Lasting eruption the 2001 explosive phase
First phase (20-24 July) the ash cloud was
produced from discrete, impulsive jets
superimposed on a continuous ash emission that
formed a stable column that produced a widespread
ash fallout eastward. Second phase (25-30 July)
fire fountaining suddenly replaced the previous
activity (cone forming phase). Final phase (31
July- 5 August) activity resumed with the same
features of the first phase but less energetic,
ash fallout covered part of the previous deposit.
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Distribution of the ash deposit on land of the
2001 eruption
5 days-long emission 5 km-high ash column Volume
0.41x106 m3 Mass erupted 540x106 kg Mass rate
1.2x103 kg s-1
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Airport cleanup during the 2002-3 eruption
Catania Fontanarossa International Airport
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Etnas ash cloud threatens aviation on the
Central Mediterranean region
28 October 2002 - Image courtesy of NASA
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A look at the past frequency of Etnas explosive
eruptions in Holocene time
10 ka - 5 ka 5.5 per ka 4 ka - present 11
per ka
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The final story 2002-03 eruption
27 October 2002 sunrise
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NE-Rift explosive activity
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Eruptive plume from the N-fissure
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28 October 2002 Strombolian activity along the
northern fissure and eruptive plume from the
southern fissure
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Bocca Nuova
SE Crater
SE Fissure
NE Crater
Voragine
Mt Etna summit
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The ash cloud above Catania
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The life in Catania town during the ash fallout
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3 November 2002
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4 December 2002
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INGV monitoring of Etnas ash clouds

• Italian Institute of Geophysics and Volcanology
  (INGV) is in charge for monitoring Etnas
  eruptive phenomena
• INGV worked with Catania International Airport
  Direction, Italian Agency for Civil Aviation
  (ENAC), Meteorological Office of Italian Air
  Force and Italian National Civil Protection for
  warning continuously the aviation authorities
  about the occurrence of ash clouds on the
  Sicilian airspace and the ash fallout on Catania
  airport
• INGV helps ENAC to set up the official procedure
  for air-traffic and airport operations in case of
  future crises due to Etnas explosive eruptions
• The lesson learned during last crisis is used
  presently to improve the volcanic ash cloud
  monitoring system of Etna volcano