Gunung Anak Krakatau

A few notes survivors of the tragedy of the eruption of Mount Krakatoa, 130 years ago, "Suddenly the world is total darkness. Tub ... Abu gush fountains of fractures floor boards. My husband cried out in despair, 'Where's the knife? I would cut the pulse ... we all suffer from being too long. '" I ran .... Pumice stabbing like needles. I realize that, my skin hanging, chipped here and there ... (Vulcan's Fury: Man Against the Volcano, A Scarth, 1999-from the pages of the geology of San Diego State University). 26-27 August 1883, the world's largest recorded volcanic eruptions ever felt modern human civilization. The first eruption occurred at 12:53, Sunday, August 26, 1883. Eruption continued with greater energy on Monday, August 27, 1883 starting at 05:30 till night. Before the eruption that killed more than 36,000 residents, those that exist along the coastline of Java and Sumatra, the tsunami swept away. On the island of Krakatau there are three mountains, namely Deeds, Danan, and Rakata. As a result of the eruption, Danan and Rakata Deeds and half collapsed, into the magma chamber and form the caldera. Two-thirds of the island was destroyed. Anak Krakatau is marked on December 29, 1927 when a number of fishermen from existing Java watched the steam and ash emerged from the caldera. Krakatau up again after 44 years of quiet. Basic data of Indonesian Volcano (Geological Agency, Energy and Mineral Resources, 2011) mentioned, Mount Anak Krakatau was born January 30, 1930. Highlight the basalt rocks up to the surface the first time on January 26, 1928. Anak Krakatau was born as a very active mountain. Starting in June last year, this mountain almost never break from volcanic activity. Volcanic earthquakes in June 2012 recorded 1,075 times, in July the incidence dropped to 807 times, but in August rose to 2,335 times the earthquake. On 2 September 2012 eruption that ejects lava. stretching Researchers geodynamics of the Faculty of Earth Sciences and Technology ITB, Irwan Meilano, said, when this happens in the middle stretch of the Sunda Strait. "This strain is derived from the Indo-Australian plate subduction of the Eurasian plate and the movement to the right of the Sumatran Fault that extends through the Sunda Strait," he said. This movement causes the eastern part of the Sunda Strait moves toward southeastern and western parts moving to the northwest. Mount Anak Krakatau complex located in the area of ​​the meeting between the Eurasian tectonic plate and the Indo-Australian in the Sunda Strait. Speed ​​of movement of the two plates is very different. The velocity of the Indo-Australian plate is about 5 centimeters (cm) per year, while the Eurasian plate speed of about 7 cm per year. Susilohadi, Head of Research and Development of Marine Geology, Research Agency, Ministry of Energy and Mineral Resources, conducted a study that confirms the occurrence of stretch in the Sunda Strait. "There were slaver (fractional Eurasian plate) in the Sumatra Fault and the subduction zone to the west of Sumatra," he said. Due to the encouragement of the Indo-Australian to the north, slaver crust move apart from the Eurasian continent to the northwest, causing the Sunda Strait in the south bay Semangko Terban (graben). "In the southern part of the Sunda Strait graben is still active," said Susilohadi. This explains the movement slaver open the Sunda Strait out into the path of magma. In the Journal of Southeast Asian Earth Sciences Vol 1, 1986, Japanese researchers from the Department of Geology and Mineralogy, Faculty of Science, Kyoto University, Susumu Nishimura, and his team who conducted the study of geology, gravity measurements, and geochemical studies confirm the emergence paleomagnetik row of volcanic activity north-south , ie Sukadana, Rajabasa, Sebesi, Sebuku, and Krakatau in the Sunda Strait along a stretch of the 200-km. Large magma source Of the row, is living and active Anak Krakatau is considered very active. The altitude has now reached 305 meters (Indonesian Volcano Data, 2011). According to Irwan, Anak Krakatau height is more than 315 meters. "Growth is very fast," said Irwan. If calculated from the eruption in 1927, after 44 years of quiet, the mountain grows 3.6 meters per year. "The condition is very active can only happen if the system extension (strain) is strong," said Irwan. Strong extension system, said Irwan, closely related to the presence of some pockets of magma below. Pockets of this active magma supply magma to the surface. From research on the pipeline system magma pockets, using termobarometrik models, it was found that the magma comes to the surface of some pockets of magma. The bags are available in a shallow layer (less than 7 km) and middle layer (7 km-22 km). In addition it was concluded that Anak Krakatau is now being enlarged and raised proceeds with the dominant silica magma. Mount the silica content of the magma eruptions are usually large, contains a lot of gas. The characters are owned by its parent first.