Krakatoa

Krakatoa

Overview
Krakatoa is a volcanic island made of a'a lava in the Sunda Strait
Sunda Strait
The Sunda Strait is the strait between the Indonesian islands of Java and Sumatra. It connects the Java Sea to the Indian Ocean...

 between the islands of Java and Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

 in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

. The name is used for the island group, the main island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

 (also called Rakata
Rakata
Rakata is a collapsed stratovolcano of the Indonesian island of Krakatoa in the Sunda Strait between the islands of Sumatra and Java. Standing tall, it was the largest and southernmost of three volcanoes that formed the island Krakatoa and the only one not totally destroyed in the eruption of 1883...

), and the volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 as a whole. The island exploded in 1883, killing approximately 40,000 people, although some estimates put the death toll much higher. The explosion is considered to be the loudest sound ever heard in modern history, with reports of it being heard nearly 3000 miles (4,828 km) from its point of origin.
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Encyclopedia
Krakatoa is a volcanic island made of a'a lava in the Sunda Strait
Sunda Strait
The Sunda Strait is the strait between the Indonesian islands of Java and Sumatra. It connects the Java Sea to the Indian Ocean...

 between the islands of Java and Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

 in Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...

. The name is used for the island group, the main island
Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

 (also called Rakata
Rakata
Rakata is a collapsed stratovolcano of the Indonesian island of Krakatoa in the Sunda Strait between the islands of Sumatra and Java. Standing tall, it was the largest and southernmost of three volcanoes that formed the island Krakatoa and the only one not totally destroyed in the eruption of 1883...

), and the volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 as a whole. The island exploded in 1883, killing approximately 40,000 people, although some estimates put the death toll much higher. The explosion is considered to be the loudest sound ever heard in modern history, with reports of it being heard nearly 3000 miles (4,828 km) from its point of origin. The shock wave
Shock wave
A shock wave is a type of propagating disturbance. Like an ordinary wave, it carries energy and can propagate through a medium or in some cases in the absence of a material medium, through a field such as the electromagnetic field...

 from the explosion was recorded on barograph
Barograph
A barograph is a recording aneroid barometer. It produces a paper or foil chart called a barogram that records the barometric pressure over time....

s around the globe.

Historical significance



The best known eruption of Krakatoa culminated in a series of massive explosions on August 26–27, 1883, which was among the most violent volcanic events in modern
Modern history
Modern history, or the modern era, describes the historical timeline after the Middle Ages. Modern history can be further broken down into the early modern period and the late modern period after the French Revolution and the Industrial Revolution...

 and recorded history
Recorded history
Recorded history is the period in history of the world after prehistory. It has been written down using language, or recorded using other means of communication. It starts around the 4th millennium BC, with the invention of writing.-Historical accounts:...

.

With a Volcanic Explosivity Index
Volcanic Explosivity Index
The Volcanic Explosivity Index was devised by Chris Newhall of the U.S. Geological Survey and Stephen Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions....

 (VEI) of 6, the eruption was equivalent to 200 MtonTNT – about 13,000 times the nuclear yield of the Little Boy
Little Boy
"Little Boy" was the codename of the atomic bomb dropped on Hiroshima on August 6, 1945 by the Boeing B-29 Superfortress Enola Gay, piloted by Colonel Paul Tibbets of the 393rd Bombardment Squadron, Heavy, of the United States Army Air Forces. It was the first atomic bomb to be used as a weapon...

 bomb (13 to 16 kt) that devastated Hiroshima, Japan, during World War II and four times the yield of the Tsar Bomba
Tsar Bomba
Tsar Bomba is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. It was also referred to as Kuz'kina Mat , in this usage meaning "something that has not been seen before"....

 (50 Mt), the largest nuclear device ever detonated.

The 1883 eruption ejected approximately 21 km³ (5 cu mi) of rock, ash, and pumice
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...

.

The cataclysmic explosion was faintly heard as far away as Perth
Perth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....

 in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

, about 1930 miles (3,106 km) away, and the island of Rodrigues
Rodrigues (island)
Rodrigues , sometimes spelled Rodriguez but named after the Portuguese explorer Diogo Rodrigues, is the smallest of the Mascarene Islands and a dependency of Mauritius...

 near Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...

, about 3000 miles (4,828 km) away.

Near Krakatoa, according to official records, 165 villages and towns were destroyed and 132 seriously damaged, at least 21,007 (official toll) people died, and many thousands were injured by the eruption, mostly from the tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...

s that followed the explosion. The eruption destroyed two-thirds of the island of Krakatoa.

Eruptions at the volcano since 1927 have built a new island in the same location, named Anak Krakatau (which is Indonesian for "Child of Krakatoa"). This island currently has a radius of roughly 2 kilometres (1.2 mi) and a high point around 324 metres (1,063 ft) above sea level , growing 5 metres (16.4 ft) each year.

Etymology and orthography


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
Western world
The Western world, also known as the West and the Occident , is a term referring to the countries of Western Europe , the countries of the Americas, as well all countries of Northern and Central Europe, Australia and New Zealand...

 was on a 1611 map by Lucas Janszoon Waghenaer
Lucas Janszoon Waghenaer
Lucas Janszoon Waghenaer was a Dutch chief officer and cartographer who was born in Enkhuizen.He is one of the founding fathers and most famous members of the North Holland school, which played a major role in the early development of Dutch nautical chart-making.Between 1550 and 1579 Waghenaer...

, who labeled the island "Pulo Carcata." (pulo is the Sundanese
Sundanese language
Sundanese is the language of about 27 million people from the western third of Java or about 15% of the Indonesian population....

 word for "island"). About two dozen variants have been found, including Crackatouw, Cracatoa, and Krakatao (in an older Portuguese-based spelling). 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 main theories are:
  • Onomatopoeia, imitating the noise made by cockatoo
    Cockatoo
    A cockatoo is any of the 21 species belonging to the bird family Cacatuidae. Along with the Psittacidae and the Strigopidae , they make up the parrot order Psittaciformes . Placement of the cockatoos as a separate family is fairly undisputed, although many aspects of the other living lineages of...

    s (Kakatoes) which used to inhabit the island. However, Van den Berg points out that these birds are found only in the "eastern part of the archipelago" (meaning the Lesser Sundas, east of Java). (See Wallace Line
    Wallace Line
    The Wallace Line separates the ecozones of Asia and Wallacea, a transitional zone between Asia and Australia. West of the line are found organisms related to Asiatic species; to the east, a mixture of species of Asian and Australian origin is present...

    ).
  • From Sanskrit
    Sanskrit
    Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

     karka or karkata or karkataka, meaning "lobster
    Lobster
    Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...

    " or "crab
    Crab
    True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...

    ". (Rakata also means "crab" in the older Javan language.) This is considered the most likely origin.
  • The closest Malay
    Malay language
    Malay is a major language of the Austronesian family. It is the official language of Malaysia , Indonesia , Brunei and Singapore...

     word is kelakatu, meaning "white-winged ant
    Ant
    Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. More than...

    ". Furneaux points out that in pre-1883 maps, Krakatoa does somewhat resemble an ant seen from above, with Lang and Verlaten lying to the sides like wings.
  • Van den Berg (1884) recites a story that Krakatau was the result of a linguistic error. According to the legend, a visiting ship's captain asked a local inhabitant the island's name, and the latter replied, "Kaga tau" (Aku enggak tahu)—a Jakarta
    Jakarta
    Jakarta is the capital and largest city of Indonesia. Officially known as the Special Capital Territory of Jakarta, it is located on the northwest coast of Java, has an area of , and a population of 9,580,000. Jakarta is the country's economic, cultural and political centre...

    n/Betawinese slang phrase meaning "I don't know". This story is largely discounted; it closely resembles other linguistic myths about the origin of the word kangaroo and the name of the Yucatán Peninsula.


The Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...

's Global Volcanism Program
Global Volcanism Program
The Smithsonian Institution's Global Volcanism Program documents Earth's volcanoes and their eruptive history over the past 10,000 years. The GVP reports on current eruptions from around the world as well as maintaining a database repository on active volcanoes and their eruptions. In this way, a...

 cites the Indonesian name, Krakatau, as the correct name but says that Krakatoa is often employed. This has been attributed to a sub-editor at The Times
The Times
The Times is a British daily national newspaper, first published in London in 1785 under the title The Daily Universal Register . The Times and its sister paper The Sunday Times are published by Times Newspapers Limited, a subsidiary since 1981 of News International...

 (who may have typographically swapped the 'a' and 'o' of the Portuguese spelling) interpreting telegraphic reporting on the massive eruption of 1883. Also, like Egypt a couple of decades earlier, Polynesia
Polynesia
Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...

 (South Pacific) was in vogue in the late 19th century, and the Polynesian-like suffix -oa (as in Samoa
Samoa
Samoa , officially the Independent State of Samoa, formerly known as Western Samoa is a country encompassing the western part of the Samoan Islands in the South Pacific Ocean. It became independent from New Zealand in 1962. The two main islands of Samoa are Upolu and one of the biggest islands in...

) may have caught on as a result. While Krakatoa is more common in the English-speaking world, the Indonesian Krakatau tends to be favored by others, including geologists. Rogier Verbeek
Rogier Verbeek
Rogier Diederik Marius Verbeek was a Dutch geologist and nature scientist.His journal Krakatau, which was edited in 1884 and 1885 by order of the Governor-General of the Dutch East Indies, is his most known work. It deals with the eruption of the volcanic island Krakatoa in 1883 and brought...

 seems to have started the modern convention of using Krakatau for the island proper and reserving Rakata for the main cone.

Geographical setting


Indonesia has over 130 active volcanoes, the most of any nation. They make up the axis of the Indonesian island arc system, which was produced by northeastward subduction of the Indo-Australian Plate
Indo-Australian Plate
The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and surrounding ocean, and extends northwest to include the Indian subcontinent and adjacent waters...

. A majority of these volcanoes lie along Indonesia's two largest islands, Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...

 and Sumatra
Sumatra
Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

. These two islands are separated by the Sunda Straits, which are located at a bend in the axis of the island arc
Island arc
An island arc is a type of archipelago composed of a chain of volcanoes which alignment is arc-shaped, and which are situated parallel and close to a boundary between two converging tectonic plates....

. Krakatoa is directly above the subduction zone of the Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...

 and the Indo-Australian Plate
Indo-Australian Plate
The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and surrounding ocean, and extends northwest to include the Indian subcontinent and adjacent waters...

 where the plate boundaries make a sharp change of direction, possibly resulting in an unusually weak crust in the region.

Before the 1883 eruption, Krakatoa comprised three main islands: Lang
Lang Island
Lang Island lies in the Sunda Strait, between Java and Sumatra, in Indonesia. It is one of the Krakatoa Islands, near the famous volcano...

 ("long," now called Rakata Kecil, or Panjang
Lang Island
Lang Island lies in the Sunda Strait, between Java and Sumatra, in Indonesia. It is one of the Krakatoa Islands, near the famous volcano...

), and Verlaten
Verlaten
Verlaten Island is an island in the Sunda Strait in Indonesia, between Java and Sumatra. It is one of the Krakatoa Islands, near the famous volcano. Other than some minor collapse in the southeast , Verlaten suffered little damage in the 1883 eruption...

 ("forsaken" or "deserted," now Sertung), which were edge remnants of a previous very large caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

-forming eruption; and Krakatoa itself, an island 9 km (5.6 mi) long by 5 km (3.1 mi) wide. Also there was a tree-covered islet near Lang named Poolsche Hoed
Poolsche Hoed
Poolsche Hoed was a small rocky islet between Krakatoa and Lang Island in the Sunda Strait. It disappeared in the 1883 eruption of Krakatoa....

 ("Polish Hat," apparently because it looked like one from the sea) and several small rocks or banks between Krakatoa and Verlaten. There were three volcanic cones on Krakatoa: Rakata
Rakata
Rakata is a collapsed stratovolcano of the Indonesian island of Krakatoa in the Sunda Strait between the islands of Sumatra and Java. Standing tall, it was the largest and southernmost of three volcanoes that formed the island Krakatoa and the only one not totally destroyed in the eruption of 1883...

, (820 m (2,690.3 ft)) to the south; Danan
Danan
Danan was one of the three volcanic cones on the island of Krakatoa, in the Sunda Strait, in Indonesia. It stood , laid in the central area of the island, and may have been a twin volcano...

, (450 m (1,476.4 ft)) to the north; and Perboewatan
Perboewatan
Perboewatan was one of the three main volcanic cones on the island of Krakatoa , in the Sunda Strait, in Indonesia. It was the lowest and northernmost of the cones...

, (120 m (393.7 ft)) to the north (Danan may have been a twin volcano).

Pre-1883 history


At some point in prehistory
Prehistory
Prehistory is the span of time before recorded history. Prehistory can refer to the period of human existence before the availability of those written records with which recorded history begins. More broadly, it refers to all the time preceding human existence and the invention of writing...

, an earlier caldera-forming eruption occurred, leaving as remnants Verlaten, Long, Poolsche Hoed, and the base of Rakata. Later, at least two more cones (Perboewatan and Danan) formed and eventually joined with Rakata, forming the main island of Krakatoa. The dating of these events is currently unknown; the Sunda Strait was first mentioned by Arab sailors around 1100 AD.

416 AD event


The Javanese
Javanese language
Javanese language is the language of the Javanese people from the central and eastern parts of the island of Java, in Indonesia. In addition, there are also some pockets of Javanese speakers in the northern coast of western Java...

 Book of Kings
Pararaton
The Pararaton, also known as the Book of Kings, is a manuscript in the Kawi language. The comparatively short text of 32 folio-size pages contains the history of the kings of Singhasari and Majapahit in eastern Java...

(Pustaka Raja) records that in the year 338 Saka
Shalivahana era
The Shalivahana era, also known as the Saka era, is used with Hindu calendars, the Indian national calendar, and the Cambodian Buddhist calendar. Its year zero begins near the vernal equinox of the year 78....

 (416 AD):
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
Sunda Strait
The Sunda Strait is the strait between the Indonesian islands of Java and Sumatra. It connects the Java Sea to the Indian Ocean...

; or it may be a mistaken date, referring to an eruption in 535 AD, for which there is some corroborating historical evidence.

535 AD event


David Keys
David Keys (author)
David Keys is archaeology correspondent for the London daily paper, The Independent, frequent television commentator on archaeological matters and author of the 1999 book Catastrophe: An Investigation into the Origins of the Modern World. He has visited over a thousand archaeological sites in sixty...

, 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. Additionally, in recent times, it has been argued that it was this eruption which created the islands of Verlaten, Lang, and the beginnings of Rakata
Rakata
Rakata is a collapsed stratovolcano of the Indonesian island of Krakatoa in the Sunda Strait between the islands of Sumatra and Java. Standing tall, it was the largest and southernmost of three volcanoes that formed the island Krakatoa and the only one not totally destroyed in the eruption of 1883...

—all indicators of early Krakatoa's caldera
Caldera
A caldera is a cauldron-like volcanic feature usually formed by the collapse of land following a volcanic eruption, such as the one at Yellowstone National Park in the US. They are sometimes confused with volcanic craters...

's size. To date, however, little datable charcoal from that eruption has been found.

Thornton (p. 47) mentions that Krakatoa was known as "The Fire Mountain" during Java's Sailendra
Sailendra
Sailendra is the name of an influential Indonesian dynasty that emerged in 8th century Java.The Sailendras were active promoters of Mahayana Buddhism and covered the Kedu Plain of Central Java with Buddhist monuments, including the world famous Borobudur.The Sailendras are considered to be a...

 dynasty, with records of seven eruptive events between the 9th and 16th centuries. These have been tentatively dated as 850, 950, 1050, 1150, 1320, and 1530 (all AD).

1680


In February 1681, Johann Wilhelm Vogel, a Dutch mining engineer at Salida, Sumatra (near Padang
Padang, Indonesia
Padang is the capital and largest city of West Sumatra, Indonesia. It is located on the western coast of Sumatra at . It has an area of and a population of over 833,000 people at the 2010 Census.-History:...

), on his way to Batavia (modern Jakarta
Jakarta
Jakarta is the capital and largest city of Indonesia. Officially known as the Special Capital Territory of Jakarta, it is located on the northwest coast of Java, has an area of , and a population of 9,580,000. Jakarta is the country's economic, cultural and political centre...

) passed through the Sunda Strait
Sunda Strait
The Sunda Strait is the strait between the Indonesian islands of Java and Sumatra. It connects the Java Sea to the Indian Ocean...

. 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
Elias Hesse
Elias Hesse was a German man who travelled through Southeast Asia in the 17th century, and the author of an account on the topic, Ost-Indische Reise-Beschreibung.Hesse was the son of a miller, born in Saxony...

, who would be called a travel writer nowadays. Hesse's journal reports that on
Vogel returned to Amsterdam in 1688 and published the first edition of his journal in 1690.

These reports of an eruption in 1680–81 pose something of a puzzle. These are the only two reports of an eruption that have been found to date, yet at the time, the Sunda Strait was one of the heaviest-travelled waterways in the world. Records for this time period are particularly detailed, because there was an intense effort to wipe out pirates that were preying on vessels in the Strait. Neither Vogel nor Hesse mention Krakatoa in any real detail in their other passings, and no other travellers at the time mention an eruption or evidence of one. (In November 1681, a pepper crop was being offered for sale.) Both Van den Berg and Verbeek conclude from this that Vogel must have exaggerated the extent of the eruption he saw. Even so, there must have been an eruption around this time, since in 1880, Verbeek investigated a fresh unweathered lava flow at the northern coast of Perboewatan, which could not have been more than a couple of centuries old.

Visit by HMS Discovery


In February 1780 the crews of HMS Resolution
HMS Resolution (Cook)
HMS Resolution was a sloop of the Royal Navy, and the ship in which Captain James Cook made his second and third voyages of exploration in the Pacific...

 and HMS Discovery
HMS Discovery (1774)
HMS Discovery was the consort ship of James Cook's third expedition to the Pacific Ocean in 1776 - 1780. Like Cook's other ships, Discovery was a Whitby-built collier of 298 tons, originally named Diligence when she was built in 1774. Originally a brig, Cook had her changed to a full rigged ship...

, on the way home after Captain James Cook
James Cook
Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...

's death in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

, stopped for a few days on Krakatoa. They found two springs on the island, one fresh water and the other hot. They described the natives who then lived on the island as "friendly" and made several sketches. (In his journal, John Ledyard
John Ledyard
John Ledyard was an American explorer and adventurer.-Early life:Ledyard was born in Groton, Connecticut, the oldest son of John and Abigail Ledyard and the nephew of Continental Army Colonel William Ledyard...

 calls the island "Cocoterra.")

Dutch activity


In 1620 the Dutch
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 set up a naval station on the islands and somewhat later a shipyard
Shipyard
Shipyards and dockyards are places which repair and build ships. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial...

 was built. Sometime in the late 17th century an attempt was made to establish a pepper
Black pepper
Black pepper is a flowering vine in the family Piperaceae, cultivated for its fruit, which is usually dried and used as a spice and seasoning. The fruit, known as a peppercorn when dried, is approximately in diameter, dark red when fully mature, and, like all drupes, contains a single seed...

 plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...

 on Krakatoa but the islands were generally ignored by Dutch colonial authorities
Dutch East India Company
The Dutch East India Company was a chartered company established in 1602, when the States-General of the Netherlands granted it a 21-year monopoly to carry out colonial activities in Asia...

. In 1809 a penal colony
Penal colony
A penal colony is a settlement used to exile prisoners and separate them from the general populace by placing them in a remote location, often an island or distant colonial territory...

 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
Sebesi
Sebesi is an Indonesian island in the Sunda Strait, between Java and Sumatra. It rises to a height of and lies about 12 km to the north of the Krakatoa Islands and is the closest large island, about the same area and height as the remmant of Rakata. Like Krakatoa, it too is volcanic, although...

 (about 12 km away) with a population of about 3,000.

Several surveys
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...

 and chart
Chart
A chart is a graphical representation of data, in which "the data is represented by symbols, such as bars in a bar chart, lines in a line chart, or slices in a pie chart"...

s were made, but mainly for the purpose of mariners, 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
Rogier Verbeek
Rogier Diederik Marius Verbeek was a Dutch geologist and nature scientist.His journal Krakatau, which was edited in 1884 and 1885 by order of the Governor-General of the Dutch East Indies, is his most known work. It deals with the eruption of the volcanic island Krakatoa in 1883 and brought...

 made an official survey of the islands but he was only allowed to spend a few hours there. He was able to collect samples from several places and his investigation proved important in judging the geological impact of the 1883 eruption.

The 1883 eruption


While seismic activity around the volcano was intense in the years preceding the cataclysmic 1883 eruption, a series of lesser eruptions beginning in mid-June 1883 led up to the disaster. The volcano released huge plumes of steam and ash lasting until late August.

On August 27 a series of four huge explosions almost entirely destroyed the island. The explosions were so violent that they were heard 3500 km (2,174.8 mi) away in Perth
Perth, Western Australia
Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....

, Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 and the island of Rodrigues
Rodrigues
Rodrigues is a common surname in the Portuguese language. It was originally a Patronymic, meaning Son of Rodrigo or Son of Rui. The "es" signifies "son of". The name Rodrigo is the Portuguese form of Roderick, meaning "famous power" or "famous ruler", from the Germanic elements "hrod" and "ric" ,...

 near Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...

, 4800 km (2,982.6 mi) away. The pressure wave from the final explosion was recorded on barograph
Barograph
A barograph is a recording aneroid barometer. It produces a paper or foil chart called a barogram that records the barometric pressure over time....

s around the world, which continued to register it up to 5 days after the explosion. The 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 (49.7 mi). The sound of the eruption was so loud it was said that if one was within ten miles (16 km), they would go deaf.

The combined effects of pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...

s, volcanic ashes, and tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...

s had disastrous results in the region. The official 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.

Average global temperatures fell by as much as 1.2 degrees Celsius in the year following the eruption. Weather patterns continued to be chaotic for years and temperatures did not return to normal until 1888.

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
Perboewatan
Perboewatan was one of the three main volcanic cones on the island of Krakatoa , in the Sunda Strait, in Indonesia. It was the lowest and northernmost of the cones...

 and Danan
Danan
Danan was one of the three volcanic cones on the island of Krakatoa, in the Sunda Strait, in Indonesia. It stood , laid in the central area of the island, and may have been a twin volcano...

. This prediction came true on 29 December 1927, when evidence of a submarine eruption was seen in this area (an earlier event in the same area had been reported in June 1927). A new island volcano, named Anak Krakatau or Child of Krakatoa, 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 faster than the waves could erode them. Of considerable interest to volcanologists
Volcanology
Volcanology is the study of volcanoes, lava, magma, and related geological, geophysical and geochemical phenomena. The term volcanology is derived from the Latin word vulcan. Vulcan was the ancient Roman god of fire....

, this has been the subject of extensive study.

Current activity


Anak Krakatau has grown at an average rate of five inches (13 cm) per week since the 1950s. This equates to an average growth of 6.8 meters per year. The island is still active, with its most recent eruptive episode having begun in 1994. Quiet periods of a few days have alternated with almost continuous Strombolian eruption
Strombolian eruption
Strombolian eruptions are relatively low-level volcanic eruptions, named after the Italian volcano Stromboli, where such eruptions consist of ejection of incandescent cinder, lapilli and lava bombs to altitudes of tens to hundreds of meters...

s since then, with occasional much larger explosions.

The eruption in April 2008 saw hot gases, rocks, and lava released. Scientists monitoring the volcano have warned people to stay out of a 3 km zone around the island. There are several videos of Krakatoa uploaded onto YouTube
YouTube
YouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos....

 showing recent footage of it erupting and inside its crater filmed at the edge of the volcano rim.

On 6 May 2009 the Volcanological Survey of Indonesia
Volcanological Survey of Indonesia
Volcanological Survey of Indonesia is the official Indonesian government body responsible for investigating, recording, and warning about volcanos within the Indonesian region of responsibility....

 raised the eruption alert status of Anak Krakatau to Level Orange.

James Reynolds posted footage to YouTube from as recently as November 1, 2010 showing some spectacular eruptions, and NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 has released satellite imagery of the recent activity.


Biological research


The islands have become a major case study of island biogeography
Island biogeography
Island biogeography is a field within biogeography that attempts to establish and explain the factors that affect the species richness of natural communities. The theory was developed to explain species richness of actual islands...

 and founder populations
Founder effect
In population genetics, the founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It was first fully outlined by Ernst Mayr in 1942, using existing theoretical work by those such as Sewall...

 in an ecosystem being built from the ground up in an environment virtually cleaned.

The islands had been little explored or 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 HMS Discovery
HMS Discovery (1774)
HMS Discovery was the consort ship of James Cook's third expedition to the Pacific Ocean in 1776 - 1780. Like Cook's other ships, Discovery was a Whitby-built collier of 298 tons, originally named Diligence when she was built in 1774. Originally a brig, Cook had her changed to a full rigged ship...

, the flora
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...

 appears to have been representative of a typical Javan tropical climax forest. The pre-1883 fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...

 is virtually unknown but was probably typical of the smaller islands in the area.

The Krakatau problem


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 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 (or brought by natives and scientific investigators). 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
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...

 in October 1916. His lease of 8.7 square kilometres (3.4 sq mi), which was basically the eastern half of the island, was 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." (Winchester gives the date of Handl's leaving as late 1917–1921.) Handl built a house and planted a garden with "4 European families and about 30 coolies". He is also believed to have introduced the black rat
Black Rat
The black rat is a common long-tailed rodent of the genus Rattus in the subfamily Murinae . The species originated in tropical Asia and spread through the Near East in Roman times before reaching Europe by the 1st century and spreading with Europeans across the world.-Taxonomy:The black rat was...

 to the island. He also found unburned wood below the 1883 ash deposits when digging, and fresh water was found below 18 feet (5.5 m).

In media



See also



  • List of volcanic eruptions by death toll
  • List of deadliest natural disasters
  • List of volcanoes in Indonesia
  • Timetable of major worldwide volcanic eruptions
    Timetable of major worldwide volcanic eruptions
    This article is a list of volcanic eruptions of approximately at least magnitude 6 on the Volcanic Explosivity Index or equivalent sulfur dioxide emission around the Quaternary period. Some cooled the global climate; the extent of this effect depends on the amount of sulfur dioxide emitted...

  • Krakatoa documentary and historical materials
    Krakatoa documentary and historical materials
    Krakatoa in the Sunda Strait in Indonesia has attracted a significant literaure and media response to the 1883 eruption.-Books:* Alfred, E. & Seward, A.C., The New Flora of the Volcanic Island of Krakatau, * Rogier Verbeek's initial report on the eruption ran in Nature in May 1884...

  • Krakatoa in media and popular culture
    Krakatoa in media and popular culture
    The 1883 eruption of Krakatoa, a volcanic island in the Sunda Strait in Indonesia, has inspired several books and films...

  • Noctilucent cloud
    Noctilucent cloud
    Night clouds or Noctilucent clouds are tenuous cloud-like phenomena that are the "ragged-edge" of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of crystals of water ice. The name means roughly night...

  • Plinian eruption
    Plinian eruption
    Plinian eruptions, also known as 'Vesuvian eruptions', are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in AD 79 ....

  • San Benedicto Island
    San Benedicto Island
    San Benedicto, formerly Santo Tomás, is an uninhabited island, and third largest island of the Revillagigedo Islands, located in the Pacific at ....

  • Volcanic Explosivity Index
    Volcanic Explosivity Index
    The Volcanic Explosivity Index was devised by Chris Newhall of the U.S. Geological Survey and Stephen Self at the University of Hawaii in 1982 to provide a relative measure of the explosiveness of volcanic eruptions....

     (includes list of large eruptions)

External links