VOLCANOES

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VOLCANOES

• VERTICAL PLUME, TEPHRA, ASHFALL, LATERAL BLAST,
  PYROCLASTIC FLOW, LAVA FLOW, LAHAR, VOLCANIC
  WINTER

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QUITO, ECUADOR
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ECUADOR

• Ecuador is a small nation with a very active and
  diverse recent volcanic history.
• Since 1999, five volcanoes have erupted
  explosively and/or effusively providing a wealth
  of geological and geophysical data.
• Quito, the capital, is located on the Equator at
  an elevation of 2800 meters ( 9,200 ft ).

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COTOPAXI VOLCANO
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COTOPAXI VOLCANO
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COTOPAXI VOLCANO
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COTOPAXI VOLCANO

• Cotopaxi volcano, located on the Eastern
  Cordillera of the Ecuadorian Andes, is a 5897
  m-high active volcano, notable for its relief
  (2000-3000 m), conical form, massive size (20 km
  diameter), and its glacier-clad steep flanks.

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COTOPAXI VOLCANO

• Historic activity corresponds to 5 cycles
  1532-34, 1742-44, 1766-68, 1853-54, and 1877-80,
  all of andesitic character that is typically
  accompanied by scoria pyroclastic flows, ash and
  lapilli falls, blocky lava flows, and
  far-reaching lahars (debris flows).

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COTOPAXI VOLCANO

• Along with other large active andesitic volcanoes
  such as Tungurahua, Antisana , Cayambe and
  Sangay, Cotopaxi forms the second volcanic row in
  Ecuador.

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COTOPAXI VOLCANO

• Rhyolitic magmatism initiated the early history
  of this volcanic center about 0.5 Ma ago.
• After a long repose, Cotopaxi became activity
  again with rhyolitic activity at 13 ka, ending at
  4.5 ka, and then switching to andesitic
  magmatism.

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COTOPAXI VOLCANO LAHARS

• Lahars are large debris flows that originate on
  volcano flanks.
• Lahars can surge tens or even hundreds of
  kilometers downstream from a volcano

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INTER ANDEAN VALLEY SITE OF MANY LAHARS
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INTER ANDEAN VALLEY

• Ecuador 's Inter Andean Valley , home to some
  three million inhabitants, is subject to the
  lahar activity of many volcanoes that border the
  valley.

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CHIMBORAZ0 VOLCANO
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CHIMBORAZO VOLCANO

• Chimborazo volcano is the highest (6268 m above
  sea level) volcano of the Ecuadorian Andes.

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TUNGURAHUA VOLCANO
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TUNGURAHUA VOLCANO

• Tungurahua volcano is one of the most active
  volcanoes of the Ecuadorian Andes.
• The ongoing eruption, which began in 1999, forced
  the temporary evacuation of the population living
  near the volcano, and severely affected both
  local and regional economies.

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EL REVENTADOR VOLCANO
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EL REVENTADOR VOLCANO

• Reventador volcano is located on the eastern
  slopes of the Ecuadorian Andes, well east of the
  principal volcanic chain.
• It is one of the most frequently active volcanoes
  in Ecuador.

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EL REVENTADOR VOLCANO

• This andesitic stratovolcano rises to 3562 m
  above the remote wild jungles of the Oriente
  basin.

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EL REVENTADOR VOLCANO

• At least 25 episodes of activity have been
  reported during historical times including lava
  flows, pyroclastic flows, and ashfalls produced
  during explosive eruptions.

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EL REVENTADOR VOLCANO

• The largest (VEI4) historical eruption at
  Reventador took place in 2002, producing a
  17-km-high eruption column, pyroclastic flows
  that traveled up to 8 km, and lava flows from
  summit and flank vents.
• A renewed activity started in November 2004,
  including the emission of 3 different lava flows
  and moderate explosive activity
• This activity was still going on in June 2005.

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GALAPAGOS VOLCANOES
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GALAPAGOS VOLCANO
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GALAPAGOS VOLCANOES

• The Galápagos are one of the world's best
  characterized sites of plume-ridge interaction
  and have some of the world's best examples of
  basaltic calderas and hydrovolcanism.
• The Galapagos volcanoes, which range from
  historical to 3 Ma, illustrate how volcanic ocean
  islands evolve.

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QUILOTOA VOLCANO
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QUILOTOA VOLCANO

• Quilotoa volcano and its summit, a small-diameter
  (lt 3 km) caldera, is located about 75 km south of
  Quito.
• During the last 40.000 years, Quilotoa volcano
  emitted crystal-rich dacite magmas as plinian
  eruptions and lava dome extrusions.

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QUILOTOA VOLCANO

• The last plinian eruption, which occurred 800 yr
  BP had a great impact on the pre-Inca human
  communities causing the displacement of
  populations towards northern regions of the
  country and triggering relevant social,
  technological and architectural changes.
• The 800 BP eruptive products exhibit
  extraordinary similarities with the 1991 Mt.
  Pinatubo eruption in the Philippines.

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PULULAHARA VOLCANO
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PULULAHUA VOLCANO

• Pululahua is a volcanic complex located 15 km
  north of Quito.
• Pululahuas volcanic development is characterized
  by three periods (1) dacitic dome effusive
  growth between 165 and 11 ka BP (2) VEI gt3
  dacitic explosive eruptions that formed the 3
  km-diameter caldera between 2545 and 2460 yr BP
  and, (3) intra-caldera acid andesite dome growth
  between 2460 and 2220 yr BP.

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PULULAHUA VOLCANO

• Pululahuas explosive eruptions caused massive
  emigration of the Cotocollao culture, which
  previously had lived close to the volcano.

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CAYAMBE AND IMBABURA VOLCANOES
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CAYAMBE AND IMBABURA VOLCANOES

• Cayambe volcano is a large, glacial-caped
  composite volcano of the Eastern Cordillera,
  which was active during Late Holocene times.
• Imbabura volcano, located in the Inter Andean
  Valley, was active in Late Pleistocene and Early
  Holocene times.

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CAYAMBE AND IMBABURA VOLCANOES

• Cayambe and Imbabura are a threat to communities
  in this highly populated area of the Andes.
• Both have produced recent pyroclastic flows and
  tephra deposits.

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CITIES AT RISK FROM VOLCANO HAZARDS