Super Volcano - Lake Toba
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The last super volcano known to erupt was the one which created Lake Toba, 74,000 years ago. Despite the fact that this super volcano occurred so long ago we can see the colossal damage it caused to the world as we know it. Animals went extinct, the air was filled with ash and sulfur, and an ice age overtook the world.

A super volcano is a volcano of proportions that we have never seen before. Unlike a regular volcano which erupts on a fairly constant basis, super volcanoes gather and store pools of thick viscous magma for thousands of years. The magma rises from a hot spot and gathers in a large open area underground. The magma creates a lot of pressure in the earth’s crust, pushing its way up it creates a bulge. Since super volcanoes have an extremely high viscosity it has an explosive release rather than a peaceful flowing type of release. When the pressure becomes too much to withstand the earth gives in and the magma ash and poisonous gas explodes out. After the magma is released the chamber it was previously held in collapses, creating a caldera. Lake Toba is an effect of a super volcano.

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Today Lake Toba is a beautiful lake, found in Sumatra, India; it is about sixty two miles long and nineteen miles wide and in some places one thousand six hundred sixty-six feet deep. It is one of the largest lakes found in Southeast Asia; and the largest volcanic lake in the world. Lake Toba is known for its fresh water which provides for the lush beautiful greenery surrounding it. It is very close to many communities and attracts business from many outside industries and businesses. When just looking at its beauty no one could guess that Lake Toba is the result of a very violent and deadly volcano.
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The volcano that is now Lake Toba has a volcanic exclusivity index of eight. That is the highest and most rare level of exclusivity. Lake Toba’s explosion is said to be the largest volcanic eruption in the past twenty-five million years.

Consequences of a super volcano are very similar to that of a regular volcano, however because it is so much bigger, it affects an extremely larger scale of living organisms. Ash, which is jagged pieces of rock and glass, also known as pumice, usually surround the area around a normal sized volcano. When a super volcano erupts its ash can reach across the world. Ash from Lake Toba, can be found all around the world, at first its existence in areas with no volcanoes confused many scientists. Lake Toba is said to have had 2,800 cubic kilometers of ash. This is an extremely big amount, especially when compared with regular volcanoes. Mount St. Helens, which is one of the largest recent volcanoes erupted in 1980, is said to have had less than one cubic kilometer. Kilauea’s 22 year long ongoing eruption is said to have made less than 2.6 cubic kilometers.


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Studies have shown that the affects of a volcano’s ash can change the weather system in the area; sometimes causing thunder storms. Knowing that the eruption of the super volcano which resulted in Lake Toba had to have had around 2,800 cubic kilometers of ash, we can understand that the results of a weather change would not be a small thunder storm, but could have pushed the world into an ice age.

Not only did the volcano at Lake Toba have an extremely larger amount of ash it also had a greater affect on the world and changed a larger area of land. The eruption took place in India; however the entire Indian subcontinent was covered with six inches of ash, and Malaysia and other areas with nine meters. The eruption might have lasted two weeks, releasing about one thousand and ten metric tons of sulphuric acid; which decreased the temperature of the globe to about 3-3.5 degrees Celsius for several years.

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It is possible for this eruption to have caused the extinction of many species or animals and plants. It would have been difficult for living things to survive, especially near the cite of the explosion. Some evidence points to the idea of the human race passing through what scientists call a “Genetic Bottleneck,” which could explain why humans are so similar in genetic makeup. Genetic Bottleneck is the idea that the genetic diversity of a specific species is reduced, and is not at the amount that is normally expected of a species of that age. Some scientists say that the population could have been reduced to only a few tens of thousands due to the eruption of the volcano that is now Lake Toba. A Genetic Bottleneck can influence social culture. Of course we cannot document and proof of this change, its very easy to describe how these change may arise. Suppose the human population was decreased by a significant factor (20% or more), then that means that the possibility of genetic diversity (mutations) is decreased because the opportunities are less frequent. If genetic diversity is slowed, then species development or adaptation will slow as well; resulting is a less adaptive and specialized species of humans. It is obvious how a significant change in genetic diversity can impact social change within the species.

Recent activity near Lake Toba consists of earthquakes and smaller scale eruptions. Pusukbukit, which is on the southwest margin of the caldera; and Tandukbeuna which is on the northwest side of the caldera edge are two volcanoes that have erupted since the major eruption approximately 74,000 years ago. We can assume that these volcanoes erupted in the last few hundred years because the vegetation around these areas is not as lush and beautiful as that of the other surrounding areas.

Common among many calderas there is uplift in the center of the caldera due to the refilling of the magma chamber underneath. The island that it formed in Lake Toba is known as Samsosir Island. Samsosir Island is at least four hundred and fifty meters. It is the largest resurgent caldera on earth.

Large earthquakes also occur in the vicinity of Lake Toba. In 1987 on the southern shore of the lake at about 11 kilometers in depth; more earthquakes followed in 1892, 1916 and 1920-1922. Lake Toba actually lies near a fault line known as Sumatra Fracture Zone. Several major earthquakes occurred on this fault zone recently. In 2004, a 9.3 earthquake occurred in the Indian Ocean; and in 2005, an 8.7 earthquake shook Sumatra, this earthquake’s epicenter was only 300 kilometers away from Lake Toba.

The volcano which resulted in Lake Toba had an extreme effect on the world. It blanketed large areas with ash, plunging the world into a very cold several years. The approximately two week explosion also points to the extinction and genetic bottlenecking of many species of plants and animals. Fortunately for us the occurrence rate of this super volcano is rare due to its extreme highness on the Volcanic Exclusivity Index. If we are lucky we will not have to worry about the reoccurrence of this volcano in our lifetime or the lifetime of our children. However, if it were to explode, how would our society and world change as we know it? Would we survive?








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