http://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa wrote:
<<The 1883 eruption of Krakatoa began in
May 1883 and culminated with the destruction of Krakatoa on 27 August 1883. Beginning 20 May 1883, three months before the final explosion, steam venting began to occur regularly from Perbuatan, the northernmost of the island's three cones. Eruptions of ash reached an altitude of 6 km and explosions could be heard in New Batavia (Jakarta) 160 km away. Activity died down by the end of May, with no records of activity until mid-June.
Eruptions started again around 16 June, when loud explosions were heard and a thick black cloud covered the islands for five days. On 24 June an east wind blew this cloud away and two ash columns were seen issuing from Krakatoa. The new seat of the eruption is believed to have been a new vent or vents which formed between Perbuatan and Danan, near the location of the volcanic cone of Anak Krakatau. The violence of the eruption caused tides in the vicinity to be unusually high, and ships at anchor had to be moored with chains as a result. Earthquake shocks began to be felt at Anyer (Java), and large pumice masses started to be reported by ships in the Indian Ocean to the west.
On 11 August, H.J.G. Ferzenaar investigated the islands. He noted three major ash columns (the newer from Danan), which obscured the western part of the island (the wind blows primarily from the east at this time of year), and steam plumes from at least eleven other vents, mostly between Danan and Rakata. Where he landed, he found an ash layer about 0.5 m thick; all vegetation had been destroyed, with only tree stumps left. He advised against any further landings. The next day, a ship passing to the north reported a new vent "only a few meters above sea level". Activity continued through mid-August.
By 25 August, eruptions further intensified. At about 13:00 (local time) on 26 August, the volcano went into its paroxysmal phase, and by 14:00 observers could see a black cloud of ash 27 km high. At this point, the eruption was virtually continuous and explosions could be heard every ten minutes or so. Ships within 20 km of the volcano reported heavy ash fall, with pieces of hot pumice up to 10 cm in diameter landing on their decks. A small tsunami hit the shores of Java and Sumatra some 40 km away between the time of 18:00 and 19:00 hours.
On 27 August four enormous explosions took place at 05:30, 06:44, 10:02, and 10:41 local time. The explosions were so violent that they were heard 3,500 km away in Perth, Western Australia and the Indian Ocean island of Rodrigues near Mauritius, 4,800 km away, where they were thought to be cannonfire from a nearby ship. Each was accompanied by very large tsunamis, which are believed to have been over 30 meters high in places. A large area of the Sunda Strait and a number of places on the Sumatran coast were affected by pyroclastic flows from the volcano. Around noon on August 27, a rain of hot ash fell around Ketimbang in Sumatra. Around a thousand people were killed, the only large number of victims killed by Krakatoa itself, and not the waves or after-effects. Verbeek and later writers believe this unique event was a lateral blast or pyroclastic surge (similar to the catastrophic 1980 eruption of Mount Saint Helens), which crossed the water. The region of the ashfall ended to the northwest of Ketimbang, where the bulk of Sebesi Island offered protection from any horizontal surges.
The pressure wave generated by the colossal final explosion radiated from Krakatoa at 1,086 km/h. It was so powerful that it ruptured the eardrums of sailors on ships in the Sunda Strait and caused a spike of more than two and half inches of mercury in pressure gauges attached to gasometers in the Jakarta gasworks, sending them off the scale. The pressure wave radiated across the globe and was recorded on barographs all over the world, which continued to register it up to 5 days after the explosion. Barograph recordings show that the shockwave from the final explosion reverberated around the globe 7 times in total. Ash was propelled to a height of 80 km. The eruptions diminished rapidly after that point, and by the morning of August 28 Krakatoa was silent.
The eruption darkened the sky worldwide for years afterwards, and produced spectacular sunsets throughout the world for many months. British artist William Ashcroft made thousands of colour sketches of the red sunsets half-way around the world from Krakatoa in the years after the eruption. In 2004, an astronomer proposed the idea that the blood-red sky shown in Edvard Munch's famous 1893 painting The Scream is also an accurate depiction of the sky over Norway after the eruption. Weather watchers of the time tracked and mapped the effects on the sky. They labeled the phenomenon the "equatorial smoke stream." This was the first identification of what is known today as the Jet stream. This eruption also produced a Bishop's Ring around the sun by day, and a volcanic purple light at twilight.>>