i very scared leh really. i wanna believe TS but please provide
as much infomration about this volcano thing as possible
so that we can read and understand how it could be so.
Sarcasm? Either way
The Toba eruption (the Toba event) occurred at what is now Lake
Toba about 67,500 to 75,500 years ago.[8] The Toba eruption was the
latest of a series of at least three caldera-forming eruptions
which have occurred at the volcano, with earlier calderas having
formed around 700,000 and 840,000 years ago. The last eruption had
an estimated VEI 8 (described as "mega-colossal"), making it
possibly the largest explosive volcanic
eruption within the last 25 million years.
Bill Rose and Craig Chesner of Michigan Technological University
have deduced that the total amount of erupted material was about
2,800 km3 (670 cu mi) —around
2,000 km3 (480 cu mi) of ignimbrite that
flowed over the ground, and around 800 km3
(190 cu mi) that fell as ash, with the wind blowing most
of it to the west. The pyroclastic flows of the eruption destroyed
an area of 20,000 km2 (7,722 sq mi), with
ash deposits as thick as 600 m (1,969 ft) by the main
vent.
The eruption was large enough to have deposited an ash layer
approximately 15 cm (5.9 in) thick over all of South
Asia; at one site in central India, the Toba ash layer today is up
to 6 m (20 ft) thick and parts of
Malaysia were covered with 9 m (30 ft) of
ashfall. In addition it has been variously calculated that
10,000 million tonnes (1.1×1010 short
tons) of sulfuric acid or 6,000 million tonnes (6.6×109 short tons) of
sulfur dioxide[14]
were ejected into the atmosphere by the event.
The subsequent collapse formed a caldera that, after filling
with water, created Lake Toba. The island in the center of the lake
is formed by a resurgent dome.
Though the year may never be precisely determined, the season
can: only the summer monsoon could have deposited Toba ashfall in
the South China Sea, implying that the eruption took place sometime
during the northern summer.[15] The eruption lasted perhaps
two weeks, but the ensuing "volcanic winter" resulted in a decrease
in average global temperatures by 3.0 to 3.5 °C (5 to
6 °F) for several years. Greenland ice cores record a pulse of
starkly reduced levels of organic carbon sequestration. Very few
plants or animals in southeast Asia would have survived, and it is
possible that the eruption caused a planet-wide die-off.
There is some evidence, based on mitochondrial DNA, that the
human species may have passed through a genetic
bottleneck around this time, reducing genetic diversity
below what would be expected from the age of the species. According
to the Toba catastrophe theory proposed by Stanley H. Ambrose of
the University of Illinois at
Urbana-Champaign in 1998, human populations may have
been reduced to only a few tens of thousands of individuals by the
Toba eruption. However, this hypothesis is not widely
accepted due to lack of evidence for any other animal decline or
extinction, even in environmentally sensitive species.
From: http://en.wikipedia.org/wiki/Lake_Toba
