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Krakatoa: 1883 Tom Demmer, Megan Hurley, Sarah Noble Volcanic Eruptions • Occur near destructive margins between tectonic plates • Eruptions spew lava (called magma while inside) and ash • Lava and ash may be deadly to those on slopes and in valleys surrounding the mountain Krakatoa • Volcanic mountain • Indonesian island of Rakata • Elevation: 2,667 feet • Famous eruption occurred in 1883 – Eruption began on June 19, 1883 – Pre- and post-eruption events went on for months • Eruption destroyed two-thirds of the island • Eruption created the loudest sound ever observed by mankind During the Eruption • Occurred on the morning of May 20, 1883 in Indonesia when the ash started to rise • For 2 months there were small eruptions • August 26-27 was when the largest explosion in historical time occurred • Last day, northern 2/3 of the island collapsed During the Eruption • Largest explosion, heard as far as Perth in Australia • Six cubic miles of rock, ash, and pumice • It was so big that debris scattered as far as Madagascar • Ash caused the formation of other islands Location and why it happened • 130 active volcanoes on Indonesia • Arc system created by subduction • Active volcano in the Sundra straits • Krakatoa’s location makes it highly explosive Results of Krakatoa • Tsunamis: – Only 1/3 of Krakatoa remained above sea level after the eruption – Wave up to 40 feet tall – Responsible for about 90% of casualties • Deadly Debris: – Falling tephra and hot protoclastic flows – About 2,000 casualties sufferd severe burns Results of Krakatoa • Atmosphere: – Fine fragments of tephra pulled into stratosphere – Decrease in temperature and exotic sky colors • Anak: – “Child of Krakatoa” Results of Krakatoa • At least 36,417 casualties • 165 coastal villages destroyed References • http://www.geology.sdsu.edu/how_volcanoes_w ork/Krakatau.html • http://www.answers.com/topic/krakatoa • http://www.geology.sdsu.edu/how_volcanoes_w ork/Thumblinks/Krak_symons_page.html • http://volcano.und.nodak.edu/vwdocs/volc_imag es/southeast_asia/indonesia/krakatau_5b.gif • http://www.geology.sdsu.edu/how_volcanoes_w ork/subducvolc_page.html • http://en.wikipedia.org/wiki/Krakatoa