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Near Extinction Of Humans.

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Presentation on theme: "Near Extinction Of Humans."— Presentation transcript:

1 Near Extinction Of Humans.

2 Toba The Super volcano. Toba the super volcano is considered an unknown phenomenon of the world. It erupted around 74,000 years ago and nearly made the entire human population extinct. It has erupted explosively a number of times over the past 1.2 millions years on the island of Sumatra in Indonesia. When the volcano had erupted it’s thought that the world population was reduced to between 10,000 and 15,ooo, this was the effect of a category 8 eruption described as ‘Mega Colossal’ At the time of the Toba eruption 74,000 years ago, humans shared the Earth with a number of similar species, including the cold-adapted Neanderthals and the dwarf Homo floresiensis. All these species made stone tools, gathered plants and hunted animals for their livelihood, and all survived the eruption and its after-effects.

3 Volcanic explosivity index.
non-explosive < 100 m 1000s m3 Hawaiian daily Kilauea 1 gentle m 10,000s m3 Haw/Strombolian Stromboli 2 explosive 1-5 km 1,000,000s m3 Strom/Vulcanian weekly Galeras, 1992 3 severe 3-15 km 10,000,000s m3 Vulcanian yearly Ruiz, 1985 4 cataclysmic 10-25 km 100,000,000s m3 Vulc/Plinian 10's of years Galunggung, 1982 5 paroxysmal >25 km 1 km3 Plinian 100's of years St. Helens, 1980 6 colossal 10s km3 Plin/Ultra-Plinian Krakatau, 1883 7 super-colossal 100s km3 Ultra-Plinian 1000's of years Tambora, 1815 8 mega-colossal 1,000s km3 10,000's of years Yellowstone, 2 Ma

4 When the volcano erupted at least 2800 cubic kilometers of volcanic material was emitted during this colossal-eruption, this volcano makes Krakatoa and Pinatubo and Mt St Helens look rather small scale. The explosion instantly killed and destroyed all animals and plants in the surrounding area, with hot flows containing billions of tonnes of ash and rock, along with ear shattering eruptions and intense Tsunamis. Rainfall and climates were greatly affected as the gasses emitted from the volcano reflected the sun away from the globe and cooled down the earth Around this time the earth was becoming so cold it was described as a portion of the ice age. The explosion.

5 The aftermath. When Toba had erupted years ago, humans were spread out from Africa into different areas e.g. southern Asia and the Middle East. Humans hadn’t reached America, Europe, or Australia, although it has been thought that 70,000 years ago, because of the ice age caused by Toba, the sea level had dropped so low that humans could island-hop their way to Australia. The volcanic winter caused by the eruption hit the small groups which greatly reduced their numbers. This is known as a population bottleneck, where the human population was reduced to as small as 10,000. The temperature and climatic effects around the world hit populations the hardest. In places where the temperatures were warmer, humans were most likely to survive ; like in tropical regions. The evidence suggests that there could have been an extinction in India roughly around the time of the eruption. The crater left by the volcano is now Lake Toba. It is 18 miles wide, 62 miles long, and is 1,666 ft its lowest point. It’s the largest volcanic lake and volcanic structure in the world. One day, the Toba super volcano will erupt again.

6 Today the crater left by the massive volcanic explosion is occupied by Lake Toba. 62 miles long, 18 miles wide, and 1,666 ft its deepest point, it is the largest volcanic lake and largest volcanic structure in the world. The island in the middle was formed by the pressure of magma below pushing up on the land. Eventually, the Toba super volcano will erupt once again.


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