Krakatoa the volcano eruption?

Question

Can you tell me the causes of Krakatoa the Effects and the responses?

ITs For Geography

Answer 1

POSSIBLE CAUSES

The cause of the violent explosions has also attracted debate. Four theories are:

- Contemporary investigators believed that the volcano's vents had sunk below sea level on the morning of 27 August, letting seawater flood into it and causing a massive series of phreatic (interaction of ground water and magma) explosions.

- The seawater could have chilled the magma, causing it to crust over and producing a "pressure cooker" effect relieved only when explosive pressures were reached.

Both these ideas assumed that the island subsided before the explosions; however, the evidence does not support that conclusion and the pumice and ignimbrite deposits are not of a kind consistent with a magma-seawater interaction.

- A massive underwater land slump or partial subsidence suddenly left the highly pressurized magma chamber wide open.

- The final explosions may have been caused by magma mixing caused by a sudden infusion of hot basaltic magma into the cooler and lighter magma in the chamber below the volcano. This would have resulted in a rapid and unsustainable increase in pressure, leading to a cataclysmic explosion. Evidence for this theory is the existence of pumice consisting of light and dark material, the dark material being of much hotter origin. However, such material reportedly is less than 5% of the content of the Krakatoa ignimbrite and some investigators have rejected this as a prime cause of the 27 August explosions.

EFFECTS

The combined effects of pyroclastic flows, volcanic ashes and tsunamis had disastrous results in the region. There were no survivors from 3,000 people located at the island of Sebesi, about 13 km from Krakatoa. Pyroclastic flows killed around 1,000 people at Ketimbang on the coast of Sumatra some 40 km north from Krakatoa. The official death toll recorded by the Dutch authorities was 36,417, although some sources put the estimate at 120,000 or more. Many settlements were destroyed, including Teluk Betung and Ketimbang in Sumatra, and Sirik and Semarang in Java. The areas of Banten on Java and the Lampung on Sumatra were devastated. There are numerous documented reports of groups of human skeletons floating across the Indian Ocean on rafts of volcanic pumice and washing up on the east coast of Africa, up to a year after the eruption. Some land on Java was never repopulated; it reverted to jungle and is now the Ujung Kulon National Park.

Answer 2

The paroxysmal explosion and collapse of the volcano of Krakatoa generated formidable tsunami waves that were up to 37 m (120 feet) in height. These waves destroyed 295 towns and villages in the Sunda Strait in Western Java and Southern Sumatra. A total of 36,417 people were drowned. The tsunami, being of volcanic origin (a point source) was only destructive locally in Indonesia. However, small tsunami waves were recorded throughout the Pacific

Answer 3

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