" KRAKATOA "
An 1888 lithograph of the 1883 eruption of Krakatoa.
Elevation813 m (2,667 ft)
Prominence813 m (2,667 ft)
Listing Spesial Ribu.
Location : LocationIndonesia Coordinates 6.102°S 105.423°E - Coordinates: 6.102°S 105.423°E.
GeologyType : Super-Caldera
Last eruption : 2012
Krakatoa, or Krakatau (Indonesian: Krakatau), is a volcanic island situated in the Sunda Strait between the islands of Java and Sumatra in Indonesia. The name is also used for the surrounding island group comprising the remnants of a much larger island of three volcanic peaks which was obliterated in a cataclysmic 1883 eruption, unleashing huge tsunamis (killing more than 36,000 people) and destroying over two-thirds of the island. The explosion is considered to be the loudest sound ever heard in modern history, with reports of it being heard up to 3,000 miles (4,800 km) from its point of origin. The shock waves from the explosion were recorded on barographs around the globe.In 1927 a new island, Anak Krakatau, or "Child of Krakatoa", emerged from the caldera formed in 1883 and is the current location of eruptive activity.
Historical :
Further information: 1883 eruption of KrakatoaThe most notable eruptions of Krakatoa culminated in a series of massive explosions over August 26–27, 1883, which were among the most violent volcanic events in recorded history.With an estimated Volcanic Explosivity Index (VEI) of 6,[2] the eruption was equivalent to 200 megatons of TNT (840 PJ) —about 13,000 times the nuclear yield of the Little Boy bomb (13 to 16 kt) that devastatedHiroshima, Japan, during World War II, and four times the yield of Tsar Bomba (50 Mt), the most powerful nuclear device ever detonated.The 1883 eruption ejected approximately 21 km3 (5.0 cu mi) of rock, ash, and pumice.[3] The cataclysmic explosion was heard in Perth in Western Australia, about 1,930 miles (3,110 km) to the south, as well as the island of Rodrigues near Mauritius, about 3,000 miles (4,800 km) to the west.[4]According to the official records of the Dutch East Indies colony, 165 villages and towns were destroyed near Krakatoa, and 132 were seriously damaged. At least 36,417 people died, and many more thousands were injured, mostly from the tsunamis that followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.Eruptions in the area since 1927 have built a new island at the same location, named Anak Krakatau (which is Indonesian for "Child of Krakatoa"). Periodic eruptions have continued since, with recent eruptions in 2009, 2010, 2011, and 2012. As of late 2011, this island has a radius of roughly 2 kilometres (1.2 mi), and a high point of about 324 metres (1,063 ft) above sea level,[5] growing 5 metres (16 ft) each year.[6]
Etymology :
Although there are earlier descriptions of an island in the Sunda Strait with a "pointed mountain," the earliest mention of Krakatoa by name in the western world was on a 1611 map by Lucas Janszoon Waghenaer, who labelled the island "Pulo Carcata" (pulo is the Sundanese word for "island"). About two dozen variants have been found, including Crackatouw, Cracatoa, and Krakatao (in an older Portuguese-based spelling). The first known appearance of the spelling Krakatau was by Wouter Schouten, who passed by "the high tree-covered island of Krakatau" in October 1658.
The origin of the Indonesian name Krakatau is uncertain.[8] The Smithsonian Institution's Global Volcanism Program cites the Indonesian name, Krakatau, as the correct name, but says that Krakatoa is often employed.[6][9][10] While Krakatoa is more common in the English-speaking world, the Indonesian Krakatau tends to be favored by others, including geologists.[citation needed]
Geographical setting :
The Sunda StraitIndonesia has over 130 active volcanoes,[11] the most of any nation. They make up the axis of the Indonesian island arc system, which was produced by northeastward subduction of the Indo-Australian Plate. A majority of these volcanoes lie along Indonesia's two largest islands, Java and Sumatra. These two islands are separated by the Sunda Strait, which is located at a bend in the axis of the island arc. Krakatoa is directly above the subduction zone of the Eurasian Plate and the Indo-Australian Plate where the plate boundaries make a sharp change of direction, possibly resulting in an unusually weak crust in the region.
