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Transcript of Mount Krakatoa
Krakatoa, or Krakatau is situated in the Sunda Strait between the islands Java and Sumatra in Indonesia. It is one of the world's most famous volcanoes.
Is it active and when did it last erupt?
The very first eruption of Krakatoa was in 1530. There have been over 47 eruptions since then, the last one was recorded in 2012. After the eruption of the volcano in 1927, there have been frequent, small explosions. Mount Krakatoa is most famous for it's violent eruption in 1883 which ruined it's structure and enlarged it's crater.
Describe the structure of the volcano.
What have been/are the effects of the eruption on people and the environment?
Tides became higher, ships needed to be chained down and there were reports of windows randomly shattering as an effect of the eruption of Krakatoa. Most of the island was destroyed due to sea water seeping into the open chamber of the volcano and exploding. Although no one was killed due to the initial explosion, the tsunamis it generated caused more than 36,000 people to die, as well as destroying many settlements. Another 1,000 or so people died from the volcanic ash that was mixed with the sea water. Dead bodies were found floating in waters near countries far from Mount Krakatoa. This shows just how widespread the damage was. The noise created by the eruption was supposedly heard in Australia, around 3,500 kilometres away.
Why did it erupt? What caused it?
What have scientists learnt from studying this eruption or similar volcanoes?
Describe the different types of rocks which have been formed.
Georgia & Sophie
A volcano constitutes a vent, a pipe, a crater, and a cone. The vent is an opening at the Earth's surface.
The pipe is a passageway in the volcano in which the magma rises through to the surface during an eruption.
The crater is a bowl-shaped depression at the top of the volcano where volcanic materials like, ash, lava, and other pyroclastic materials are released.
Solidified lava, ashes, and cinder form the cone. Layers of lava, alternate with layers of ash to build the steep sided cone higher and higher.
At 12:53 p.m. on Sunday the 26th, the initial blast of the eruption sent a cloud of gas and debris an estimated 24 km into the air above Perboewatan. It is thought that rubble from the earlier eruptive activity must have plugged the neck of the cone, allowing pressure to build in the magma chamber. On the morning of the 27th, four tremendous explosions, heard as far away as Perth, Australia.The island of Krakatoa is in the Sunda Strait between Java and Sumatra. It is part of the Indonesian Island Arc. Volcanic activity is due to decrease of the Indo-Australian tectonic plate as it moves northward towards mainland Asia.
3 main types of volcanoes, and each has been formed from a different type of magma. Once the lava has erupted, it cools and solidifies into rock:
•Basalt magma often forms shield volcanoes.
•Andesite magma often forms cone volcanoes.
•Rhyolite magma often forms calderas. Depending on how much gas the magma contains, it can also form cone volcanoes.
Scientists believe that Krakatoa will erupt again, this time causing much more damage then the time before. Other scientist don't believe that it will erupt again as there is not enough magma. Scientists are doing their best to minimise the risk of another eruption.