Eruption+of+Krakatoa

=== ** The eruption of Krakatoa in 1883 is one of the most violent geophysical events in history ** ===

=== //**K**// rakatoa was located in the waters of the Sunda Strait in Indonesia. It was set between the islands of Java and Sumatra. During its one-million-year history it first evolved into a cone shaped mountain 1828m above sea level. Over the centuries a number of eruptions reduced it so that by 1883 its highest point reached to 813m. ===

[[image:http://www.ees1.lanl.gov/Wohletz/Krakatau3.jpg align="left"]]Huge blast
In may 1883, after 200 years of silence, Krakatoa began to erupt. On 20 May a large explosion was recorded, and there were further eruptions on 19 June, although these were nothing compared with what was coming. About a month later, on 26 August at 1.00 p.m., Krakatoa began to make increasingly violent explosions. 21 hours later, on 27 August at 10.00 a.m., the biggest explosion took place as the explosion caused the island to collapse to a magma chamber. 23 cubic km of the island cave in to a 6 km-diameter caldera.

The noise of the blast was heard even in Rodriquez Island in the Indian Ocean, 4653 km away from Krakatoa. A huge pillar of ash 80 km high reached into the atmosphere, and the waves of the explosion were picked up by every barograph on the planet. Even after five days some barographs recorded the travel of the air waves.

** Destrutive force **
=== The eruption of Krakatoa was one of the biggest explosions in history, equivalent to around 200 megatons of TNT. Even the most devastating man created, a hydrogen bomb, couldn't match this kind of explosion. The explosion also blasted out 21 cubic km of rock, and more than 800 000 sq km of territory were affected by ash fallout. Pyroclastic flows left no survivors on the Sebesi Island they also destroyed the coast of Sumatra, killing in process over 1000 people. Some of the flows were still deadly hot even 40km away from Krakatoa. ===

The explosion caused a number of tsunamis and increased the variability of tides. The highest tsunamis, some of them over 40m high, hit the coastlines of Java and Sumatra, killing over 36 000 people. Tsunamis hit as far as to the shore of South Africa. Smaller waves were seen even as far as the English Channel.

**Coldhouse effect**
==== Krakatoa's eruption sent a great amount of ash and especially sulfur dioxide to the stratosphere. The amount of sunlight slightly decreased because of them, and this caused global temperatures to go down about 1.2°C until 1888. The amount of ash in the atmosphere also created spectacular sunsets, made the sun look like a green or blue ball and the sky red. ====

By Kirill & Tuomo

http://static.astronomija.co.rs/nauke/geologija/vulkani/Vulkani/Opasni_vulkani/Krakatoa/Krakatao.jpg http://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa Chris McNab: The world's worst historical disasters
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