wwww.krakatauecotour.com
Early in the morning of May 20, 1883, the captain of the German warship Elizabeth reported seeing an ~11-km-high cloud of ash and dust rising above the uninhabited island of Krakatau, thus documenting the first eruption from this Indonesian island in at least two centuries. Over the ensuing two months, crews on commercial vessels and sightseers on charted ships would experience similar spectacles, all of which were associated with explosive noises and churning clouds of black to incandescent ash and pumice. From a distance, the largest of these natural fanfares impressed the local inhabitants on the coastal plains of Java and Sumatra, creating a near-festive environment. Little did they realize, however, that these awe-inspiring displays were only a prelude to one of the largest eruptions in historic times. A series of cataclysmic explosions began at mid-day on August 26, and ended on August 27 with a stupendous paroxysmal eruption. On this day, the northern two-thirds of the island collapsed beneath the sea, generating a series of devasting pyroclastic flows and immense tsunamis that ravaged adjacent coastlines. The events that began on August 26 would mark the last 24 hours on earth for over 36,000 people, and the destruction of hundreds of coastal villages and towns.
ndonesia contains over 130 active volcanoes, more than any other country on earth. They comprise the axis of the Indonesian island arc system, which is generated by northeastward subduction of the Indo-Australian plate. The great majority of these volcanoes lie along the topographic crest of the arc's two largest islands - Java and Sumatra. The islands are separated by the Sunda Straits, which is located at a distinct bend in axis of the island arc volcanoes, from a nearly east-west orientation in Java to a northwest-southeast orientation in Sumatra. Krakatau is one of a several volcanic islands in the Sunda Straits located above an active north-northeast trending fault zone, an orientation quite distinct from the main island-arc trend. Although relatively small when compared to the largest volcanoes along the island arc, Krakatau and its associated volcanoes have shown the capacity to generate highly explosive eruptions.
Tuesday, August 25, 2009
krakatau ecotour
Overview
On August 27th, 1883 a series of blasts on the island of Krakatoa culminated in a colossal explosion that blew the island apart in one of the largest eruptions in recorded history. Below are a few brief facts about the blast and its effects.
1. The 23km square island of Krakatoa existed at a height of 450m above sea level. The blast leveled most of the island to 250m below sea level.
2. Pyroclastic flows traveled as far as 40km from the island consuming traversing ships in fire and ash.
3. The sound of the final explosion was heard over 4500km away and covered 1/13th of the Earth's surface.
4. The eruption generated tsunamis 40m high that devastated nearby coastlines.
5. The final death toll from pyroclastic flows, volcanic bombs, and tsunamis was calculated to be a devastating 36,417.
Geography and Geology
The island of Krakatoa is located in the Sundra Straits between the islands of Java and Sumatra off the southwestern coast of Indonesia. Krakatoa is one of many active volcanoes along the Indonesian Island Arc, including the famous Tambora volcano. This arc, containing over 130 active volcanoes, is produced by the subduction of the Indo-Australian plate as it moves northward towards mainland Asia.
The island of Krakatoa itself is lies next to two other islands: Lang and Verlaten. These three islands together are the remains of an ancient volcanic island. Ancient Krakatoa, as it is called, exploded in an enormous eruption around 416 A.D., according to Javanese scriptures. In that eruption the majority of the island collapsed into a 7km long caldera beneath Rakata on Krakatoa forming the three present day islands.
The map on the right shows Krakatoa as it was before the great eruption of 1833. Three major volcanoes existed on the island, Perboewetan, Danan(not shown but in the middle), and Rakata. Since the eruption and collapse of Ancient Krakatoa the chamber beneath these three volcanoes had begun to fill, heat up, and create enormous pressure. Of late, Perboewetan had been the most active.
On August 27th, 1883 a series of blasts on the island of Krakatoa culminated in a colossal explosion that blew the island apart in one of the largest eruptions in recorded history. Below are a few brief facts about the blast and its effects.
1. The 23km square island of Krakatoa existed at a height of 450m above sea level. The blast leveled most of the island to 250m below sea level.
2. Pyroclastic flows traveled as far as 40km from the island consuming traversing ships in fire and ash.
3. The sound of the final explosion was heard over 4500km away and covered 1/13th of the Earth's surface.
4. The eruption generated tsunamis 40m high that devastated nearby coastlines.
5. The final death toll from pyroclastic flows, volcanic bombs, and tsunamis was calculated to be a devastating 36,417.
Geography and Geology
The island of Krakatoa is located in the Sundra Straits between the islands of Java and Sumatra off the southwestern coast of Indonesia. Krakatoa is one of many active volcanoes along the Indonesian Island Arc, including the famous Tambora volcano. This arc, containing over 130 active volcanoes, is produced by the subduction of the Indo-Australian plate as it moves northward towards mainland Asia.
The island of Krakatoa itself is lies next to two other islands: Lang and Verlaten. These three islands together are the remains of an ancient volcanic island. Ancient Krakatoa, as it is called, exploded in an enormous eruption around 416 A.D., according to Javanese scriptures. In that eruption the majority of the island collapsed into a 7km long caldera beneath Rakata on Krakatoa forming the three present day islands.
The map on the right shows Krakatoa as it was before the great eruption of 1833. Three major volcanoes existed on the island, Perboewetan, Danan(not shown but in the middle), and Rakata. Since the eruption and collapse of Ancient Krakatoa the chamber beneath these three volcanoes had begun to fill, heat up, and create enormous pressure. Of late, Perboewetan had been the most active.
Friday, April 24, 2009
krakatau tour
www.krakatauecotour.com
The eruption of Krakatau were recorded effectively in 1882 due to the emerging telegraphic system at that time and the fact that it is located in the Sunda strait, the frequently-used shipping lane.
The Krakatau Volcano has a long and seemingly never ending history. It was gathered from ancient Javanese scriptures that in 416 AD a great volcano called Ancient Krakatau in the Sunda strait collapsed, forming a 7 km wide caldera and leaving its remnants in the form of three islands: the Krakatau island, Verlaten island and Lang island. Not long after, three coalesced volcanoes called Perboewatan, Danan and Rakata were formed in the same area. These are the volcanoes forming the island of Krakatau.
This whole island is the object causing the legendary eruption of 1883. On May 20th 1883 ashes and steams started to rise from its craters, followed by moderate explosions, all of them relatively not taken seriously. In fact, people simply gathered round in a fascination to watch the island’s sights and sounds. Therefore, it must have been a devastating shock indeed when the whole Krakatau island and its entire seabed finally exploded on the morning of August 27th 1883. The explosion was so loud that those in Indian Ocean’s Rodriquez Island, 4.563 Kms away, could hear the bang. The Krakatau’s volcanic dust and gases reached the stratosphere and circled the world in two weeks. The whole Perboewatan and Lang island and half of Rakata Island collapsed into the submarine caldera below and its cavity-filling effect caused tsunamis with prodigious heights that could only be outdone by the 2004 Aceh Tsunami.
Even though the Krakatau island is uninhabited, the disaster’s effects were inescapable for the people surrounding the area. Most of them became victims of the tsunami, the tallest of its waves reaching 40 meters, swallowing up people and surrounding villages. 165 villages were totally destroyed and another 132 damaged. Ships in the Lampung bay, Sumatra, were lifted and thrown away as far as a mile inland.
There were also victims of the pyroglastic flows, which enigmatically traveled in a wondrous speed of over 100 km per hour across the ocean. The flows, their temperature presumably reaching over 700 degrees, were thought to have created a smooth ‘path’ made of steam which was created by flash-boiling the surface of the ocean. The Southern part of Sumatera was known to be the worst part to be hit by these flows. The pyroglastic flows, along with avalanches of fires and rocks, are literally rivers of fire, swallowing up everything in their way.
The death toll of the 1883 Krakatau Disaster reached up to 36,417. In the aftermath, the world temperature dropped down a few degrees due to a mixture of water and sulfur dioxide in the air which blocked the sunlight. Visual effects in the sky such as halos caused by this additional ‘screen’ were also a common sight for a few years.
In 1927, a new cone inside the 1883 caldera was discovered. The cone is properly named ‘Anak Krakatau’ (child of Krakatau) and its height had been increasing with time. Eruptions of this volcano have been recorded several times.
The eruption of Krakatau were recorded effectively in 1882 due to the emerging telegraphic system at that time and the fact that it is located in the Sunda strait, the frequently-used shipping lane.
The Krakatau Volcano has a long and seemingly never ending history. It was gathered from ancient Javanese scriptures that in 416 AD a great volcano called Ancient Krakatau in the Sunda strait collapsed, forming a 7 km wide caldera and leaving its remnants in the form of three islands: the Krakatau island, Verlaten island and Lang island. Not long after, three coalesced volcanoes called Perboewatan, Danan and Rakata were formed in the same area. These are the volcanoes forming the island of Krakatau.
This whole island is the object causing the legendary eruption of 1883. On May 20th 1883 ashes and steams started to rise from its craters, followed by moderate explosions, all of them relatively not taken seriously. In fact, people simply gathered round in a fascination to watch the island’s sights and sounds. Therefore, it must have been a devastating shock indeed when the whole Krakatau island and its entire seabed finally exploded on the morning of August 27th 1883. The explosion was so loud that those in Indian Ocean’s Rodriquez Island, 4.563 Kms away, could hear the bang. The Krakatau’s volcanic dust and gases reached the stratosphere and circled the world in two weeks. The whole Perboewatan and Lang island and half of Rakata Island collapsed into the submarine caldera below and its cavity-filling effect caused tsunamis with prodigious heights that could only be outdone by the 2004 Aceh Tsunami.
Even though the Krakatau island is uninhabited, the disaster’s effects were inescapable for the people surrounding the area. Most of them became victims of the tsunami, the tallest of its waves reaching 40 meters, swallowing up people and surrounding villages. 165 villages were totally destroyed and another 132 damaged. Ships in the Lampung bay, Sumatra, were lifted and thrown away as far as a mile inland.
There were also victims of the pyroglastic flows, which enigmatically traveled in a wondrous speed of over 100 km per hour across the ocean. The flows, their temperature presumably reaching over 700 degrees, were thought to have created a smooth ‘path’ made of steam which was created by flash-boiling the surface of the ocean. The Southern part of Sumatera was known to be the worst part to be hit by these flows. The pyroglastic flows, along with avalanches of fires and rocks, are literally rivers of fire, swallowing up everything in their way.
The death toll of the 1883 Krakatau Disaster reached up to 36,417. In the aftermath, the world temperature dropped down a few degrees due to a mixture of water and sulfur dioxide in the air which blocked the sunlight. Visual effects in the sky such as halos caused by this additional ‘screen’ were also a common sight for a few years.
In 1927, a new cone inside the 1883 caldera was discovered. The cone is properly named ‘Anak Krakatau’ (child of Krakatau) and its height had been increasing with time. Eruptions of this volcano have been recorded several times.
Subscribe to:
Comments (Atom)
