Toba: Super Volcano in Sumatra

Apparently Sumatra has a super volcano located very close to where all the earthquakes took place. It erupted 74,000 years ago and was the largest eruption in the last 200,000 years.

www.bbc.co.uk
The last supervolcano to erupt was Toba 74,000 years ago in Sumatra. Ten thousand times bigger than Mt St Helens, it created a global catastrophe dramatically affecting life on Earth. Scientists know that another one is due - they just don't know when... or where.....

.....Climatologists now know that Toba blasted so much ash and sulphur dioxide into the stratosphere that it blocked out the sun, causing the Earth's temperature to plummet. Some geneticists now believe that this had a catastrophic effect on human life, possibly reducing the population on Earth to just a few thousand people.

Toba on the map:


Where the earthquakes took place:



The Toba Caldera fault zone:



More info on the Toba Caldera:

Toba caldera produced the largest eruption in the last 2 million years. The caldera is 18 x 60 miles (30 by 100 km) and has a total relief of 5,100 feet (1700 m). The caldera probably formed in stages. Large eruptions occurred 840,000, about 700,000, and 75,000 years ago. The eruption 75,000 years ago produced the Young Toba Tuff. The Young Toba Tuff was erupted from ring fractures that surround most or all of the present-day lake.

Comparison of volumes produced by some of the greatest volcanic eruptions. The Young Toba Tuff has an estimated volume of 2,800 cubic kilometers (km) and was erupted about 74,000 years ago. The Huckleberry Ridge Tuff, erupted at Yellowstone 2.2 million years ago, has a volume of 2,500 cubic km. The Lava Creek Tuff, erupted at Yellowstone 600,000 years ago, has a volume of 1,000 cubic km. The May 1980 eruption of Mount St. Helens produced 1 cubic km of ash. Not shown is the Fish Canyon Tuff of the San Juan Mountains of Colorado. The Fish Canyon Tuff was erupted 27.8 million years ago and has an estimated volume of 3,000 cubic km.

The volume of the youngest eruption is estimated at 2,800 cubic km, making the eruption the largest in the Quaternary. Pyroclastic flows covered an area of at least 20,000 square km. Up to 1200 feet (400 m) of Young Toba Tuff is exposed in the walls of the caldera. On Samosir Island the tuff is more than 1800 feet (600 m) thick. Ash fall from the eruption covers an area of at least 4 million square km (about half the size on the continental United States). Ash from the eruption has been recovered from deep-sea cores taken in the Bay of Bengal and in India, roughly 300 miles (500 km) inland (1,900 miles, 3100 km from Toba). Rose and Chesner suggested the ash may have reached central Asia and the Middle East. Ninkovich and others (1978) estimated of the height of the eruption column to be 30 to 50 miles (50 to 80 km) for the Young Toba Tuff. Rose and Chesner, after a study of the shapes of the ash shards, concluded this estimate was too high by a factor of 5 or more.

I'm quite certain that the earthquakes and the supervolcano are quite unrelated, but it's interesting any way.

Sorry for all the quoting but I'm no geologist.

Pistol Pete, that's a good post indeed. If you're interested in old volcanoes in general and Java/Sumatra ones in particular, you might want to get a book by David Keys called: "Catastrophe: An Investigation into the Origins of Modern Civilization" (www.amazon.com...).

I think you'd really enjoy it.

Originally posted by Off_The_Street
Pistol Pete, that's a good post indeed. If you're interested in old volcanoes in general and Java/Sumatra ones in particular, you might want to get a book by David Keys called: "Catastrophe: An Investigation into the Origins of Modern Civilization" (www.amazon.com...).

I think you'd really enjoy it.

Cool off_the_street, I'll look into it! Reading the description it sounds like something up my alley.

I just got done sifting through: Guns, Germs and Steel: The Fates of Human Society, by Jared Diamond. How we got where we are I believe is just as important as where we're going.

Originally posted by Off_The_Street
If you're interested in old volcanoes in general and Java/Sumatra ones in particular, you might want to get a book by David Keys called: "Catastrophe: An Investigation into the Origins of Modern Civilization"

First off great post Pete!

OTS - Did PBS do a "Secrets of the Dead" on Keys theory? I remember one of their programs in the series was called Catastrophe and the global impact a volcanic eruption in the area of Sumatra had on the whole planet sometime during the 6th century.


B.

PistolPete, interesting that you bring this to our attention.. look what continues to go on in that area...


DATE LAT LON MAG DEPTH REGION
05-JAN-2005 05:32:38 3.57 93.62 5.5 30.0 OFF W COAST OF NORTHERN SUMATERA
04-JAN-2005 19:58:03 -10.41 41.04 5.2 10.0 NORTHWEST OF MADAGASCAR
04-JAN-2005 19:14:49 10.60 91.74 5.8 10.0 ANDAMAN ISLANDS, INDIA
04-JAN-2005 19:08:02 5.16 94.64 5.4 30.0 NORTHERN SUMATERA, INDONESIA
04-JAN-2005 18:26:45 4.98 94.79 5.6 53.1 OFF W COAST OF NORTHERN SUMATERA
04-JAN-2005 12:56:00 6.53 93.00 5.2 30.0 NICOBAR ISLANDS, INDIA
04-JAN-2005 12:15:33 8.84 93.69 5.1 30.0 NICOBAR ISLANDS, INDIA
04-JAN-2005 09:13:12 10.67 92.40 6.0 24.7 ANDAMAN ISLANDS, INDIA
04-JAN-2005 02:04:46 4.47 93.12 4.9 30.0 OFF W COAST OF NORTHERN SUMATERA

Not that it has anything to with a Super Valcano getting primed again, but who knows... The Earth continues to shake allot within that area.

I like a visual most of the time.. I keep this site up while at Work,
www.iris.edu...
Enjoy.

The Toba caldera is a fascinating subject to me, especially the aspect of its last eruption *theoretically* causing a population bottleneck and nearly eradicating the human race.

Here are some good sites on the bottleneck side of things:
www.jqjacobs.net...
www.bradshawfoundation.com...
en.wikipedia.org...

Kind of makes one feel really, really small in the scope of things, doesn't it....?

Yeah Catastrophe is a great read... but the volcano used as a example there has erupted in the last 150 years so i think we're safe from that one

who knows what volcanoes it might stir up.i would be very causation right now living near a type of fault line or a volcano new or old.if those plates keep shaking who knows.flukemol........

Originally posted by specialasianX
Yeah Catastrophe is a great read... but the volcano used as a example there has erupted in the last 150 years so i think we're safe from that one

What volcano?
Tambora's eruption caused year without summer but eruption was in 1815.

Originally posted by specialasianX
but the volcano used as a example there has erupted in the last 150 years so i think we're safe from that one

I believe you're thinking of Krakatoa, not Toba.
Toba is on a much larger scale than Krakatoa, which is a huge volcano to begin with.

A full eruption of Toba would make Krakatoa look like a sneeze, unfortunately.

Hey guys, are the quakes that are happening in Northern Sumatra close to this volcano? Does some one have the lat/long on this?

Okay, it looks as though the caldera is bounded as follows:

2.0 - 3.0 N
98.4 - 99.2 E

The northern Sumatra quakes are happening around:

5.5 N
94.5 E

Originally posted by Banshee
I believe you're thinking of Krakatoa, not Toba.
Toba is on a much larger scale than Krakatoa, which is a huge volcano to begin with.

Krakatoa... that small backyard campfire.

Total energy release of eruption was only ~200 Mt altough third and last "bang" equivalent to ~150 Mt caused generally over 10 meters high tsunami and over 30 meters in "best" places while destroying most of island. (that which didn't fly to the sky collapsed to caldera)
Also shockwaves of explosion were detected only seven times with barographs when they made "couple" rounds around the globe.

And Lang and Verlaten (with Krakatoa) were propably parts of bigger island which collapsed to caldera in bigger eruption in the past. (compare to Santorini)


www.drgeorgepc.com...

I just saw on tv that a volcano in Indenosia had just errupted. I dont know if its toba though.

www.abovetopsecret.com...

An post on this theme is already running...

I recommend the book Krakatoa 'The day the world Exploded' by Simon Winchester... It mentions the eruption in Catastrophe (also a great read) in 530 AD, but is mainly concenred

Krakatoa explains how the Subduction fault that virtually cuts through Java and Sumatra works. Judging from all seismic activity in the area right now, it wouldnt suprise me if there was another large eruption like the 530 or 1883 Krakatoa eruptions, or Pinotubo, or Tambora... or worse yet Lake Toba... i'm keeping my eyes and ears open on this one.