Krakatoa
Krakatoa, or Krakatau, is a caldera in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The caldera is part of a volcanic island group comprising four islands: two of which, Lang and Verlaten, are remnants of a previous volcanic edifice destroyed in eruptions long before the famous 1883 eruption; another, Rakata, is the remnant of a much larger island destroyed in the 1883 eruption.
In 1927, a fourth island, Anak Krakatau, or "Child of Krakatoa", emerged from the caldera formed in 1883. There has been new eruptive activity since the late 20th century, with a large collapse causing a deadly tsunami in December 2018.
Historical significance
The most notable eruptions of Krakatoa culminated in a series of massive explosions over 26–27 August 1883, which were among the most violent volcanic events in recorded history.With an estimated Volcanic Explosivity Index of 6, the eruption was equivalent to —about 13,000 times the nuclear yield of the Little Boy bomb that devastated Hiroshima, Japan, during World War II, and four times the yield of Tsar Bomba, the most powerful nuclear device ever detonated at 50 Mt.
The 1883 eruption ejected approximately of rock. The cataclysmic explosion was heard away in Alice Springs, Australia, and on the island of Rodrigues near Mauritius, to the west.
According to the official records of the Dutch East Indies colony, 165 villages and towns were destroyed near Krakatoa, and 132 were seriously damaged. At least 36,417 people died, and many more thousands were injured, mostly from the tsunamis that followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.
Eruptions in the area since 1927 have built a new island at the same location, named Anak Krakatau. Periodic eruptions have continued since, with recent eruptions in 2009, 2010, 2011, and 2012, and a major collapse in 2018. In late 2011, this island had a radius of roughly, and a highest point of about above sea level, growing each year.
In 2017, the height of Anak Krakatau was reported as over above sea level; following a collapse in December 2018, the height was reduced to 110 meters.
Etymology
Although there are earlier descriptions of an island in the Sunda Strait with a "pointed mountain," the earliest mention of Krakatoa by name in the western world was on a 1611 map by Lucas Janszoon Waghenaer, who labelled the island "Pulo Carcata". About two dozen variants have been found, including Crackatouw, Cracatoa, and Krakatao. The first known appearance of the spelling Krakatau was by Wouter Schouten, who passed by "the high tree-covered island of Krakatau" in October 1658.The origin of the Indonesian name Krakatau is uncertain.
The Smithsonian Institution's Global Volcanism Program cites the Indonesian name, Krakatau, as the correct name, but says that Krakatoa is often employed.
Geographical setting
Indonesia has over 130 active volcanoes, the most of any nation. They make up the axis of the Indonesian island arc system produced by northeastward subduction of the Indo-Australian Plate. A majority of these volcanoes lie along Indonesia's two largest islands, Java and Sumatra. These two islands are separated by the Sunda Strait located at a bend in the axis of the island arc. Krakatau is directly above the subduction zone of the Eurasian Plate and the Indo-Australian Plate where the plate boundaries make a sharp change of direction, possibly resulting in an unusually weak crust in the region.Pre-1883 history
At some point in prehistory, an earlier caldera-forming eruption had occurred, leaving as remnants Verlaten ; Lang ; Poolsche Hoed ; and the base of Rakata. Later, at least two more cones formed and eventually joined with Rakata, forming the main island of Krakatoa. At the time of the 1883 eruption, the Krakatoa group comprised Lang, Verlaten, and Krakatoa itself, an island long by wide. There were also the tree-covered islet near Lang and several small rocky islets or banks between Krakatoa and Verlaten.There were three volcanic cones on Krakatoa island: Rakata, to the south; Danan, near the center; and Perboewatan, to the north.
416 AD event
The Javanese Book of Kings records that in the year 338 Saka :There is no geological evidence of a Krakatoa eruption of this size around that time; it may describe loss of land which previously joined Java to Sumatra across what is now the narrow east end of the Sunda Strait; or it may be a mistaken date, referring to a later eruption in 535 AD, for which there is some corroborating historical evidence.
535 AD event
, Ken Wohletz, and others have postulated that a violent volcanic eruption, possibly of Krakatoa, in 535 may have been responsible for the global climate changes of 535–536. Keys explores what he believes to be the radical and far-ranging global effects of just such a putative 6th-century eruption in his book Catastrophe: An Investigation into the Origins of the Modern World. This eruption was believed to have been even more violent than Krakatoa's 1883 eruption, and also the one that created Krakatoa's original caldera, which resulted in the creation of Verlaten Island and Lang Island. However, there are other explanations for the climate change, including an eruption of Ilopango in El Salvador, in Central America.Thornton mentions that Krakatoa was known as "The Fire Mountain" during Java's Sailendra dynasty, with records of seven eruptive events between the 9th and 16th centuries. These have been tentatively dated as having occurred in 850, 950, 1050, 1150, 1320, and 1530.
1680
In February 1681, Johann Wilhelm Vogel, a Dutch mining engineer at Salida, Sumatra, on his way to Batavia passed through the Sunda Strait. In his diary he wrote:Vogel spent several months in Batavia, returning to Sumatra in November 1681. On the same ship were several other Dutch travellers, including Elias Hesse, a writer. Hesse's journal reports:
The eruption was also reported by a Bengali sea captain, who wrote of the event later, but had not recorded it at the time in the ship's log. Neither Vogel nor Hesse mention Krakatoa in any real detail in their other passages, and no other travellers at the time mention an eruption or evidence of one. In 1880, Verbeek investigated a fresh unweathered lava flow at the northern coast of Perboewatan, which could not have been more than two centuries old.
Visit by HMS ''Discovery''
In February 1780, the crews of and, on the way home after Captain James Cook's death in Hawaii, stopped for a few days on Krakatoa. They found a freshwater and a hot spring on the island. They described the natives who then lived on the island as "friendly" and made several sketches.Visit by USS ''Peacock''
calls the island Crokatoa in his journal. A paraphrased account follows: On 8 September 1832, US sloop-of war Peacock anchored off the north end, also visiting Lang Island, in search of inhabitants, fresh water, and yams. It was found difficult to land anywhere, due to a heavy surf and to the coral having extended itself to a considerable distance from the shore. Hot springs boiling furiously up, through many fathoms of water, were found on the eastern side of Krakatoa, from the shore. Roberts, Captain Geisinger, and marine lieutenant Fowler visited Forsaken island, having mistaken the singing of locusts for the sound of running water. The boat glided over crystal clear water, over an extensive and highly beautiful submarine garden. Corals of every shape and hue were there, some resembling sunflowers and mushrooms, others cabbages from in diameter, while a third type bore a striking likeness to the rose. The hillsides were typical of tropical climate; large flocks of parrots, monkeys in great variety, wild-mango and orange groves—a superb scene of plants and flowers of every description, glowing in vivid tints of purple, red, blue, brown, and green—but not water or provisions.Dutch activity
In 1620, the Dutch set up a naval station on the islands and somewhat later a shipyard was built. Sometime in the late 17th century, an attempt was made to establish a pepper plantation on Krakatoa, but the islands were generally ignored by the Dutch East India Company. In 1809, a penal colony was established at an unspecified location, which was in operation for about a decade. By the 1880s, the islands were without permanent inhabitants; the nearest settlement was the nearby island of Sebesi with a population of 3,000.Several surveys and mariners' charts were made, and the islands were little explored or studied. An 1854 map of the islands was used in an English chart, which shows some difference from a Dutch chart made in 1874. In July 1880, Rogier Verbeek made an official survey of the islands, but was only allowed to spend a few hours there. He was able to collect samples from several places, and his investigation later proved important in judging the geological impact of the 1883 eruption.
1883 eruption
While seismic activity around the volcano was intense in the years preceding the cataclysmic 1883 eruption, a series of lesser eruptions began on 20 May 1883. The volcano released huge plumes of steam and ash lasting until late August.On 27 August, a series of four huge explosions almost entirely destroyed the island. The explosions were so violent that they were heard away in Perth, Western Australia, and the island of Rodrigues near Mauritius, away. The pressure wave from the third and most violent explosion was recorded on barographs around the world. Several barographs recorded the wave seven times over the course of five days: four times with the wave travelling away from the volcano to its antipodal point, and three times travelling back to the volcano; the wave rounded the globe three and a half times. Ash was propelled to a height of. The sound of the eruption was so loud it was reported that if anyone was within, they would have gone deaf.
The combined effects of pyroclastic flows, volcanic ashes, and tsunamis had disastrous results in the region and worldwide. The death toll recorded by the Dutch authorities was 36,417, although some sources put the estimate at more than 120,000. 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. Summer temperatures in the northern hemisphere fell by an average of in the year following the eruption.
Aftermath
Anak Krakatau
Verbeek, in his report on the eruption, predicted that any new activity would manifest itself in the region which had been between Perboewatan and Danan. This prediction came true on 29 December 1927, when a submarine lava dome in the area of Perboewatan showed evidence of eruptions. A new island volcano rose above the waterline a few days later. The eruptions were initially of pumice and ash, and that island and the two islands that followed were quickly eroded away by the sea. Eventually, a fourth island, named Anak Krakatau, broke water in August 1930 and produced lava flows more quickly than the waves could erode them.Biological research
The islands have become a major case study of island biogeography and founder populations in an ecosystem being built from the ground up in an environment virtually cleaned.The islands had been little studied or biologically surveyed before the 1883 catastrophe—only two pre-1883 biological collections are known: one of plant specimens and the other part of a shell collection. From descriptions and drawings made by, the flora appears to have been representative of a typical Javan tropical climax forest. The pre-1883 fauna is virtually unknown, but was probably typical of the smaller islands in the area.
Botanical studies
From a biological perspective, the Krakatau problem refers to the question of whether the islands were completely sterilized by the 1883 eruption or whether some indigenous life survived. When the first researchers reached the islands in May 1884, the only living thing they found was a spider in a crevice on the south side of Rakata. Life quickly recolonized the islands, however; Verbeek's visit in October 1884 found grass shoots already growing. The eastern side of the island has been extensively vegetated by trees and shrubs, presumably brought there as seeds washed up by ocean currents or carried in birds' droppings. It is, however, in a somewhat fragile position, and the vegetated area has been badly damaged by recent eruptions.Handl's occupancy
A German, Johann Handl, obtained a permit to mine pumice in October 1916. His lease of , was to be for 30 years. He occupied the south slope of Rakata from 1915 to 1917, when he left due to "violation of the terms of the lease." Handl built a house and planted a garden with "four European families and about 30 coolies". It is his party that is believed to have inadvertently introduced the black rat to the island. Handl found un-burned wood below the 1883 ash deposits while digging, and fresh water was found below.Popular culture
A large part of the 1947 children's novel The Twenty-One Balloons by William Pene du Bois takes place on Krakatoa, where several families have established a wealthy and fanciful colony based on fictional diamond mines on the island.Krakatoa has been featured as a subject and a part of the story in various television and film dramas. In the 1953 film Fair Wind to Java, an American sea captain and a pirate leader race one another to recover a fortune in diamonds hidden on Krakatoa, which begins its final eruption as they search the island for the treasure. The island was a prominent part of the plot of '"Crack of Doom," episode six of the Irwin Allen television series The Time Tunnel in 1966. It was also featured as the main part of the story line in the 1969 film, Krakatoa, East of Java, which depicts an effort to salvage a priceless cargo of pearls located perilously close to the erupting volcano. An Indonesian martial arts action film, Krakatau, starring Dicky Zulkarnaen and Advent Bangun, also set the story on the mountain. In more recent years, it has been the subject of a 2006 television drama, Krakatoa: Volcano of Destruction and again in 2008 as Krakatoa.
In Klaus Teuber's board game Seafarers of Catan, the "Krakatoa Variant" is a scenario involving an island composed of three volcano tiles.
In 1973, the American progressive rock band Styx released a spoken-word track called "Krakatoa" on its album The Serpent Is Rising. Written by then-guitarist John Curulewski along with Paul Beaver and Bernie Krause, the song tells the story of Krakatoa's eruption and the subsequent return of life to the island.
The British heavy metal band Saxon also released a song about the 1883 eruption of Krakatoa, called "Krakatoa", on the 2010 re-release of its 1985 album Innocence Is No Excuse.