The Volcanic Explosivity Index (VEI) was devised by Chris Newhall
of the U.S. Geological Survey and Steve Self at the University of
Hawai?i in 1982 to provide a relative measure of the explosiveness
of volcanic eruptions.
Volume of products, eruption cloud height, and qualitative observations
(using terms ranging from "gentle" to "mega-colossal") are used to determine
the explosivity value. The scale is open-ended with the largest volcanoes
in history given magnitude 8. A value of 0 is given for non-explosive
eruptions (less than 104 cubic metres of tephra ejected) with 8
representing a mega-colossal explosive eruption that can eject 1012
cubic metres of tephra and have a cloud column height of over 25 km (16 mi).
Each interval on the scale represents a tenfold increase in observed eruption criteria.
Note that ash, volcanic bombs, and ignimbrite are all treated alike —
this is due to taking into account the vesicularity (gas bubbling) of the
volcanic products in question and the DRE (Dense-Rock Equivalent) is calculated
to give the actual amount of magma erupted. One weakness of the VEI is
that it does not take into account the magnitude of power output of an eruption.
This, of course, is extremely difficult to detect with prehistoric or unobserved eruptions.
6. 1982 Eruption of Galunggung, (VEI 4)
Mount Galunggung (Indonesian: Gunung Galunggung,
formerly spelled Galoen-gong) is an active stratovolcano in West Java, Indonesia.
The last major eruption on Galunggung was in 1982, which had a Volcanic
Explosivity Index of 4 and killed 68 people. This eruption also brought
the dangers of volcanic ash to aviation to worldwide attention, after two Boeing
747 passenger jets flying downwind of the eruption suffered temporary
engine failures and damage to exterior surfaces, both planes being forced
to make emergency landings at Jakarta.
one, a British Airways aircraft carrying 240 passengers, accidentally entered the
ash cloud during night time in June 1982 150 km downwind of the volcano.
All four engines failed and the aircraft descended for 16 minutes, losing 7500
metres of its 11500 meter altitude, until the crew managed to restart the engines.
The following month a Singapore Airlines aeroplane with 230 passengers aboard
also inadvertently entered the cloud at night time, and three of its four engines stopped.
The crew succeeded in restarting one of the engines after descending 2400 meters.
Both aircraft suffered serious damage to their engines and exterior surfaces.
5. The 1963-64 Eruption of Mount Agung, (VEI 5)
Mount Agung or Gunung Agung is a mountain in Bali, Indonesia.
This stratovolcano is the highest point on the island. It dominates the
surrounding area influencing the climate. The clouds come from the west and
Agung takes their water so that the west is lush and green and the east dry and barren.
The Balinese believe that Mount Agung is a replica of Mount Meru,
the central axis of the universe. One legend holds that the mountain is a
fragment of Meru brought to Bali by the first Hindus. The most important
From the peak of the mountain, it is possible to see the peak of
Mount Rinjani on the island of Lombok, although both mountains are frequently
covered in clouds.On February 18, 1963, local residents heard loud explosions
and saw clouds rising from the crater of Mount Agung. On February 24,
lava began flowing down the northern slope of the mountain, eventually traveling
7 km in the next 20 days. On March 17, the volcano erupted, sending
debris 8–10 km into the air and generating massive pyroclastic flows. These flows
devastated numerous villages, killing approximately 1500 people.
Cold lahars caused by heavy rainfall after the eruption killed an additional 200.
A second eruption on May 16 led to pyroclastic flows which killed
another 200 inhabitants.The lava flows missed, sometimes by mere yards,
the Mother Temple of Besakih. The saving of the temple is regarded
by the Balinese people as miraculous and a signal from the gods
that they wished to demonstrate their power but not destroy the
monument the Balinese faithful had erected.
4. 1883 Eruption of Krakatoa, (VEI 6)
Krakatoa (Indonesian: Krakatau), also spelled Cracatoa or Krakatau,
is a volcanic island made of a'a lava in the Sunda Strait between
the islands of Java and Sumatra in Indonesia. The name is used for
the island group, the main island (also called Rakata), and the volcano as a whole.
The best-known eruption of Krakatua culminated in a series of massive
explosions on August 26–27, 1883, which was among the
most violent volcanic events in modern and recorded history.
With a Volcanic Explosivity Index (VEI) of 6, the eruption was
equivalent to 200 megatons of TNT (840 PJ)—about 13,000 times the
nuclear yield of the Little Boy bomb (13 to 16 kT) that devastated Hiroshima,
Japan during World War II and four times the yield of the Tsar Bomba (50 MT),
the largest nuclear device ever detonated
The 1883 eruption ejected approximately 21 cubic kilometres (5.0 cu mi)
of rock, ash, and pumice.
The cataclysmic explosion was distinctly heard as far away as Perth in Western
Australia, about 1,930 miles (3,110 km) away, and the island of Rodrigues
near Mauritius, about 3,000 miles (5,000 km) away.
Near Krakatau, according to official records, 165 villages and towns were
destroyed and 132 seriously damaged, at least 36,417 (official toll) people died,
and many thousands were injured by the eruption, mostly from the tsunamis that
3. Maninjau (280.000 BP), (VEI 7)
Lake Maninjau (Indonesian: Danau Maninjau, meaning overlook or
observation in Minangkabau) is a caldera lake in West Sumatra, Indonesia.
2. 1815 Eruption of Tambora, (VEI 7)
Mount Tambora (or Tamboro) is an active stratovolcano, also known as
a composite volcano, on the Sumbawa islands, Indonesia. Sumbawa is flanked
both to the north and south by oceanic crust, and Tambora was formed by
the active subduction zones beneath it. This raised Mount Tambora as high as
4,300 m (14,100 ft), making it one of the tallest peaks in the Indonesian archipelago,
and drained off a large magma chamber inside the mountain. It took decades to
During an excavation in 2004, a team of archaeologists discovered cultural
remains buried by the 1815 eruption. They were kept intact beneath
the 3 m (9.8 ft) deep pyroclastic deposits. At the site, dubbed the Pompeii
In 1812, Mount Tambora became highly active, with its eruptive peak in the
catastrophic explosive event of April 1815. The magnitude was seven on the
Volcanic Explosivity Index (VEI) scale, with a total tephra ejecta volume
of 1.6 × 1011 cubic metres (160 cubic kilometers or 38 cubic miles).
It was an explosive central vent eruption with pyroclastic flows and a caldera collapse,
causing tsunamis and extensive land and property damage. It created a long-term
effect on global climate. This activity ceased on 15 July 1815. Follow-up activity
was recorded in August 1819 consisting of a small eruption (VEI = 2) with flames
and rumbling aftershocks, and was considered to be part of the 1815 eruption.
Around 1880 ± 30 years, Tambora went into eruption again, but only inside the caldera.
It created small lava flows and lava dome extrusions. This eruption (VEI = 2)
created the Doro Api Toi parasitic cone inside the caldera.
Mount Tambora is still active. Minor lava domes and flows have been extruded
on the caldera floor during the 19th and 20th centuries. The last eruption
was recorded in 1967. However, it was a very small,
non-explosive eruption (VEI = 0).
1. The Toba Super Eruption, (VEI 8)
The Toba supereruption (Young Toba Tuff or simply YTT) occurred between
69,000 and 77,000 years ago at Lake Toba (Sumatra, Indonesia),
and it is recognized as one of Earth's largest known eruptions.
The related catastrophe theory holds that this supervolcanic event plunged
the planet into a 6 to 10 year volcanic winter, which resulted in the world's
human population being reduced to 10,000 or even a mere 1,000 breeding pairs,
creating a bottleneck in human evolution. Some researchers argue that the
Toba eruption produced not only a catastrophic volcanic winter but also an
additional 1,000 year cooling episode.
The Toba event is the most closely studied supereruption. In 1993,
Michael R. Rampino of the New York University and Stephen Self of the
University of Hawaii at Manoa first suggested a link between the eruption
and a bottleneck in human evolution. The theory was then developed in 1998
Although the eruption took place in Indonesia, it deposited an ash layer approximately
15 centimetres thick over the entire Indian subcontinent. A blanket of
volcanic ash was also deposited over the Indian Ocean, and the Arabian
and South China Sea. Studies, based on deep-sea cores retrieved from
the South China Sea, recently extended the known distribution of the eruption, and
suggest that the ~2,800 km3 calculation of the eruption magnitude is a minimum
value or even an under-estimate.
Source:
http://vulcan.wr.usgs.gov/
http://volcanoes.usgs.gov/
http://www.bbc.co.uk/
http://dsc.discovery.com/
http://volcano.si.edu/
http://geo.mtu.edu/
http://id.wikipedia.org/
http://kaskus.us/
http://www.tobavolcano.googlepages.com/
http://www.articlesextra.com/toba-supervolcano-indonesia.htm
http://mediaranahjaya.blogspot.com/
of the U.S. Geological Survey and Steve Self at the University of
Hawai?i in 1982 to provide a relative measure of the explosiveness
of volcanic eruptions.
Volume of products, eruption cloud height, and qualitative observations
(using terms ranging from "gentle" to "mega-colossal") are used to determine
the explosivity value. The scale is open-ended with the largest volcanoes
in history given magnitude 8. A value of 0 is given for non-explosive
eruptions (less than 104 cubic metres of tephra ejected) with 8
representing a mega-colossal explosive eruption that can eject 1012
cubic metres of tephra and have a cloud column height of over 25 km (16 mi).
Each interval on the scale represents a tenfold increase in observed eruption criteria.
Note that ash, volcanic bombs, and ignimbrite are all treated alike —
this is due to taking into account the vesicularity (gas bubbling) of the
volcanic products in question and the DRE (Dense-Rock Equivalent) is calculated
to give the actual amount of magma erupted. One weakness of the VEI is
that it does not take into account the magnitude of power output of an eruption.
This, of course, is extremely difficult to detect with prehistoric or unobserved eruptions.
6. 1982 Eruption of Galunggung, (VEI 4)
Mount Galunggung (Indonesian: Gunung Galunggung,
formerly spelled Galoen-gong) is an active stratovolcano in West Java, Indonesia.
The last major eruption on Galunggung was in 1982, which had a Volcanic
Explosivity Index of 4 and killed 68 people. This eruption also brought
the dangers of volcanic ash to aviation to worldwide attention, after two Boeing
747 passenger jets flying downwind of the eruption suffered temporary
engine failures and damage to exterior surfaces, both planes being forced
to make emergency landings at Jakarta.
one, a British Airways aircraft carrying 240 passengers, accidentally entered the
ash cloud during night time in June 1982 150 km downwind of the volcano.
All four engines failed and the aircraft descended for 16 minutes, losing 7500
metres of its 11500 meter altitude, until the crew managed to restart the engines.
The following month a Singapore Airlines aeroplane with 230 passengers aboard
also inadvertently entered the cloud at night time, and three of its four engines stopped.
The crew succeeded in restarting one of the engines after descending 2400 meters.
Both aircraft suffered serious damage to their engines and exterior surfaces.
5. The 1963-64 Eruption of Mount Agung, (VEI 5)
Mount Agung or Gunung Agung is a mountain in Bali, Indonesia.
This stratovolcano is the highest point on the island. It dominates the
surrounding area influencing the climate. The clouds come from the west and
Agung takes their water so that the west is lush and green and the east dry and barren.
The Balinese believe that Mount Agung is a replica of Mount Meru,
the central axis of the universe. One legend holds that the mountain is a
fragment of Meru brought to Bali by the first Hindus. The most important
Gunung Agung last erupted in 1963-64 and is still active, with a large and very
deep crater which occasionally belches smoke and ash. From a distance,
the mountain appears to be perfectly conical, despite the existence of the large crater.
Mount Rinjani on the island of Lombok, although both mountains are frequently
covered in clouds.On February 18, 1963, local residents heard loud explosions
and saw clouds rising from the crater of Mount Agung. On February 24,
lava began flowing down the northern slope of the mountain, eventually traveling
7 km in the next 20 days. On March 17, the volcano erupted, sending
debris 8–10 km into the air and generating massive pyroclastic flows. These flows
devastated numerous villages, killing approximately 1500 people.
Cold lahars caused by heavy rainfall after the eruption killed an additional 200.
A second eruption on May 16 led to pyroclastic flows which killed
another 200 inhabitants.The lava flows missed, sometimes by mere yards,
the Mother Temple of Besakih. The saving of the temple is regarded
by the Balinese people as miraculous and a signal from the gods
that they wished to demonstrate their power but not destroy the
monument the Balinese faithful had erected.
4. 1883 Eruption of Krakatoa, (VEI 6)
Krakatoa (Indonesian: Krakatau), also spelled Cracatoa or Krakatau,
is a volcanic island made of a'a lava in the Sunda Strait between
the islands of Java and Sumatra in Indonesia. The name is used for
the island group, the main island (also called Rakata), and the volcano as a whole.
The best-known eruption of Krakatua culminated in a series of massive
explosions on August 26–27, 1883, which was among the
most violent volcanic events in modern and recorded history.
With a Volcanic Explosivity Index (VEI) of 6, the eruption was
equivalent to 200 megatons of TNT (840 PJ)—about 13,000 times the
nuclear yield of the Little Boy bomb (13 to 16 kT) that devastated Hiroshima,
Japan during World War II and four times the yield of the Tsar Bomba (50 MT),
the largest nuclear device ever detonated
The 1883 eruption ejected approximately 21 cubic kilometres (5.0 cu mi)
of rock, ash, and pumice.
The cataclysmic explosion was distinctly heard as far away as Perth in Western
Australia, about 1,930 miles (3,110 km) away, and the island of Rodrigues
near Mauritius, about 3,000 miles (5,000 km) away.
Near Krakatau, according to official records, 165 villages and towns were
destroyed and 132 seriously damaged, at least 36,417 (official toll) people died,
and many thousands were injured by the eruption, mostly from the tsunamis that
followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.
Eruptions at the volcano since 1927 have built a new island in the same location,
This island currently has a radius of roughly 2 kilometres (1.2 mi)
and a high point around 300 metres (980 ft) above sea level, growing 5 metres
(16 ft) each year.
3. Maninjau (280.000 BP), (VEI 7)
Lake Maninjau (Indonesian: Danau Maninjau, meaning overlook or
observation in Minangkabau) is a caldera lake in West Sumatra, Indonesia.
It is located 16 km to the west of Bukittinggi, at 0°19'S 100°12'E.
occurred around 52,000 years ago. Deposits from the eruption have been
found in a radial distribution around Maninjau extending up to 50 km to
the east, 75 km to the southeast, and west to the present coastline.
The deposits are estimated to be distributed over 8500 km² andnhave a
volume of 220–250 km³. The caldera has a length of 20 km and a width of 8 km.
2. 1815 Eruption of Tambora, (VEI 7)
Mount Tambora (or Tamboro) is an active stratovolcano, also known as
a composite volcano, on the Sumbawa islands, Indonesia. Sumbawa is flanked
both to the north and south by oceanic crust, and Tambora was formed by
the active subduction zones beneath it. This raised Mount Tambora as high as
4,300 m (14,100 ft), making it one of the tallest peaks in the Indonesian archipelago,
and drained off a large magma chamber inside the mountain. It took decades to
refill the magma chamber, its volcanic activity reaching its peak in April 1816.
Tambora erupted in 1816 with a rating of seven on the Volcanic Explosivity Index,
making it the largest eruption since the Lake Taupo eruption in about 180 CE.
The 1815 eruption of Tambora was the largest volcanic eruption in recorded history.
The explosion was heard on Sumatra island (more than 2,000 km (1,200 mi) away).
Heavy volcanic ash falls were observed as far away as Borneo, Sulawesi,
Java and Maluku islands. Most deaths from the eruption were from starvation and
disease, as the eruptive fallout ruined agricultural productivity in the local region.
The death toll was at least 71,000 people (the most deadly eruption in recorded history),
of whom 11,000–12,000 were killed directly by the eruption; the often-cited figure
of 92,000 people killed is believed to be an overestimate. The eruption created
global climate anomalies; 1816 became known as the "Year Without a Summer
" because of the effect on North American and European weather.
Agricultural crops failed and livestock died in much of the Northern Hemisphere,
resulting in the worst famine of the 19th century.
remains buried by the 1815 eruption. They were kept intact beneath
the 3 m (9.8 ft) deep pyroclastic deposits. At the site, dubbed the Pompeii
of the East, the artifacts were preserved in the positions they had occupied in 1815.
Tambora had erupted three times before the 1815 eruption, but the magnitudes
of these eruptions are unknown. Their estimated dates are 3910 BC ± 200 years,
3050 BC and 740 CE ± 150 years. They were all explosive central vent eruptions
with similar characteristics, except the lattermost eruption had no pyroclastic flows.
catastrophic explosive event of April 1815. The magnitude was seven on the
Volcanic Explosivity Index (VEI) scale, with a total tephra ejecta volume
of 1.6 × 1011 cubic metres (160 cubic kilometers or 38 cubic miles).
It was an explosive central vent eruption with pyroclastic flows and a caldera collapse,
causing tsunamis and extensive land and property damage. It created a long-term
effect on global climate. This activity ceased on 15 July 1815. Follow-up activity
was recorded in August 1819 consisting of a small eruption (VEI = 2) with flames
and rumbling aftershocks, and was considered to be part of the 1815 eruption.
Around 1880 ± 30 years, Tambora went into eruption again, but only inside the caldera.
It created small lava flows and lava dome extrusions. This eruption (VEI = 2)
created the Doro Api Toi parasitic cone inside the caldera.
Mount Tambora is still active. Minor lava domes and flows have been extruded
on the caldera floor during the 19th and 20th centuries. The last eruption
was recorded in 1967. However, it was a very small,
non-explosive eruption (VEI = 0).
1. The Toba Super Eruption, (VEI 8)
The Toba supereruption (Young Toba Tuff or simply YTT) occurred between
69,000 and 77,000 years ago at Lake Toba (Sumatra, Indonesia),
and it is recognized as one of Earth's largest known eruptions.
The related catastrophe theory holds that this supervolcanic event plunged
the planet into a 6 to 10 year volcanic winter, which resulted in the world's
human population being reduced to 10,000 or even a mere 1,000 breeding pairs,
creating a bottleneck in human evolution. Some researchers argue that the
Toba eruption produced not only a catastrophic volcanic winter but also an
additional 1,000 year cooling episode.
The Toba event is the most closely studied supereruption. In 1993,
Michael R. Rampino of the New York University and Stephen Self of the
University of Hawaii at Manoa first suggested a link between the eruption
and a bottleneck in human evolution. The theory was then developed in 1998
by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign.
The Toba eruption or Toba event occurred at what is now Lake Toba about
73,500 years (± 3,000 years) or 73,000 (± 4,000 years) ago. The Toba eruption
was the latest of the three major eruptions which occurred at Toba in the last
1 million years. The last eruption had an estimated Volcanic Explosivity Index
of 8 (described as "mega-colossal"), or magnitude = M8; it thus made a sizeable
contribution to the 100 X 30 km caldera complex. Dense-rock equivalent
estimated of eruptive volume for the eruption vary between 2,000 km3 and
3,000 km3, but the most frequently quoted DRE is ~2,800 km3 (7 X 10km18g)
of erupted magma, of which 800 km3 was deposited as ash fall. It was two
orders of magnitude greater in erupted mass than the largest volcanic eruption
in historic times, in 1815 at Mount Tambora in Indonesia, which made 1816
the "Year Without a Summer" in the northern hemisphere.
Although the eruption took place in Indonesia, it deposited an ash layer approximately
15 centimetres thick over the entire Indian subcontinent. A blanket of
volcanic ash was also deposited over the Indian Ocean, and the Arabian
and South China Sea. Studies, based on deep-sea cores retrieved from
the South China Sea, recently extended the known distribution of the eruption, and
suggest that the ~2,800 km3 calculation of the eruption magnitude is a minimum
value or even an under-estimate.
Source:
http://vulcan.wr.usgs.gov/
http://volcanoes.usgs.gov/
http://www.bbc.co.uk/
http://dsc.discovery.com/
http://volcano.si.edu/
http://geo.mtu.edu/
http://id.wikipedia.org/
http://kaskus.us/
http://www.tobavolcano.googlepages.com/
http://www.articlesextra.com/toba-supervolcano-indonesia.htm
http://mediaranahjaya.blogspot.com/
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