<P> 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 . </P> <P> The origin of the Indonesian name Krakatau is uncertain . </P> <P> The Smithsonian Institution's Global Volcanism Program cites the Indonesian name, Krakatau, as the correct name, but says that Krakatoa is often employed . While Krakatoa is more common in the English - speaking world, the Indonesian Krakatau tends to be favored by others, including geologists . </P> <P> Indonesia has over 130 active volcanoes, the most of any nation . They make up the axis of the Indonesian island arc system 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 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 . </P>

When was the last time krakatoa volcano erupted