greetings best friend steemians,
Mount Krakatoa became the most popular volcano for Indonesian people especially through the horror of the eruption in 1883. In general perception, this is the greatest volcano rampage in the historical era, although it is not true. Just 68 years before Krakatoa released its rage, Mount Tambora on the island of Sumbawa (now part of the province of West Nusa Tenggara) erupted so violently with its peak on April 11, 1815. He spewed a hot magma burning in quantity eight times more than Krakatoa 1883. Energy eruption was so great. Collect all the nuclear warheads in the two superpowers at the height of the Cold War (ie the US and USSR) then blast into one together, then the explosive energy still has not exceeded the greatness of the 1815 Tambora Eruption.
krakatoa.credit image
However, let's ignore Tambora for a while and we focus attention on Krakatoa. Before August 1883, this volcano was just an ordinary small island lined with a number of other islands in the Sunda Strait such as Sertung (Verlaten), Small Rakata (Lang), Sebesi and Sebuku Islands. Krakatoa Island is oval shaped about 7 kilometers long and decorated with three hills like a hill. Rows from southeast to northwest, all three are Rakata (798 meters above sea level), Danan (500 meters above sea level) and Perbuwatan (130 meters above sea level). These three bumps are actually undersea volcanoes, which grew after a massive 1200 eruption (exact year unknown) in the region. In the development of the three undersea volcanoes are increasingly enlarged so that finally poked over the Sunda Strait and eventually all three bodies together into Krakatau island. This small island was inhabited by humans with agrarian life, complete with rice fields and plantations. Dutch Indies colonial navy even had time to build a shipyard here. But early in the nineteenth century when Indonesia switched to a brief British occupation, the island of Krakatoa was abandoned for no apparent reason. So gradually everything turns into a beautiful jungle and beautiful like heaven. But in August 1883, the beautiful paradise was instantly turned into a hot hell burning when the three peaks on the island of Krakatoa erupted with a fierce.
Evolution of the islands around Krakatoa from 1880 to 2005. Note the continuing growth of Anak Krakatoa after the 1883 event..credit image
The eruption of Krakatoa in 1883 was very popular as the greatest natural disaster for Indonesia after the eruption of Tambora 1815 and lasted more than a century later. The record was just toppled in late 2004 when the massive Sumatra-Andaman earthquake of 26 December 2004 exploded. The death toll from this enormous eruption reached 36,417 people, according to official records of the Dutch East Indies colonial government. But recent scientists estimate the actual toll is far greater, perhaps even reaching the number of 120,000 people. Almost completely killed by the tremendous tsunami that formed as a result of the collapse of the island of Krakatoa accompanied by the formation of the large caldera and the injection of volcanic material in large numbers to the base of the Sunda Strait. But among the victims, there are about 1,000 people who were killed exposed to the volcanic material of the vomit of Krakatoa. All of them are from Katimbang, now known as Katibung, adjacent to Kalianda and become part of Lampung province. This is a heart-wrenching story, which is really hot because it involves such a high and burning temperature.
Katimbang
Katimbang is a coastal area of the Sunda Strait in the western leg of Mount Rajabasa which is known to be fertile plantation area productive. It is about 37 kilometers to the north of Krakatoa island.
In February 1883 there had been a thrill for the vibrations felt in Katimbang. The vibrations are small intensity and do not cause damage or panic, but take place continuously within a certain period of time and then stop. Now the science of modern volcanoes knows that at that time magma fresh in the amount of very large and very thick is starting to flow from the kitchen of magma Krakatoa nun far in the depth of tens of kilometers to the magma pockets located just below the mountain.
Three months later, exactly May 9, 1883, again recorded a vibration after vibration in Katimbang, but this time feels quite hard and starts scary. No one knows what caused it. But now we know, by that time the fresh magma had reached the magma sack and was struggling to crack the layers of rock that blocked its way to the top. Vibration after vibration culminated in the first eruption, which spurted from the peak of Perbuwatan on May 20, 1883. Concerned volcanic dust and gas sprayed up to 11 kilometers. The fishermen in the Sunda Strait, as well as woodcutters for shipbuilding materials in Katimbang became witnesses, even the captain of Lindeman with the Loudon steam crew. And only a few moments later the powerful air pressure blows hit Katimbang, without any impact. Similar hatch felt the instrument of the weather station barometer Dr. Vanderstock in Batavia, 160 kilometers from Krakatoa. But there was no significant impact on Katimbang after this first eruption. The island of Krakatoa then continued to actively spray out its volcanic gases and dust for four months later.
Map of the Sunda Strait .credit image
Katimbang really feels the magnitude of the eruption of Krakatau on Sunday afternoon August 26, 1883. At 17:07 local, Krakatoa island into the most deadly phase begins with a very loud banging from the top of Perbuwatan which is heard in all directions, even up to 5,000 kilometers from the mountain. This sound is recorded as the harshest sound ever seen on Earth until now. Concentrated volcanic dust and gas sprayed to as high as 27 kilometers. Some of Krakatoa island especially around the top of Perbuwatan destroyed until only the remaining giant crater with a diameter of 1 kilometer. The air pressure waves (shock waves) that are released in combination with the subsequent series of subsequent eruptions result in high waves pounding as tsunamis. Then only about an hour later, when the sun goes down, Katimbang receives the brunt of his tsunami. As a result, people's homes and facilities near the shoreline were destroyed. It is fortunate that most of the population of Katimbang have fled first to a dense forest on the slopes of Mount Rajabasa which are located higher. But no one knows that in just a few hours they will be faced with the most horrible situation in the eruption of Krakatoa.
After a rowdy night and smoldering by a series of eruptions after the eruption of Krakatoa following each other after every 10 minutes like a mitraliur shot, on Monday 27 August 1883 this mountain reached the peak of its eruption. The enormous eruption, which dissipates more than 15 cubic kilometers of volcanic spice that includes more than 75% of the total magma spewed by Krakatoa Eruption 1883, occurred at 10:02 local time. A massive tsunami was formed, with a wave height of up to a hundred meters at the beginning and immediately marched into all sides of the Sunda Strait at speeds of less than 100 km / h. As it spreads, it also rummages through the narrow waters of the sea until the coral boulders are uprooted from its roots. Both the coast of Java and Sumatra immediately soaked the tsunami with an altitude of between 15 to 33 meters.
The tsunami did not affect the people of Katimbang who had fled to the forest. But suddenly strong winds lunged followed by bursts of dust as soft as a hot powder that immediately crushed the refuge on the slopes of the mountain. The impact is quite deadly. Of the 3,000 residents of Katimbang who took refuge in the jungle, about 1,000 of them died instantly dying with bodies roasted or disappeared under a pile of dust. While the rest did not escape the horror of others, full of burns on the body at various levels.
Horizontal Eruption
The hot spill of dust that enveloped Katimbang was suddenly global and popular as the event of the Burning Ash of Katimbang. This event could make dizziness of experts of earth and volcano that time. Why not. There is no doubt that the super-hot dust as smooth as the powder that hit Katimbang is part of the hot cloud, the volcanic material of eruption products in the form of sand and dust mixed with volcanic gas all of which are high temperatures. All the material glide rolled up to look like a cloud and from here the word 'hot cloud' was started.
Is this event one of the most remarkable features of a volcanic eruption? Apparently not too. In the 1991 (Philippines) Pinatubo Eruption which spewed magma up to more than half of the 1883 Krakatoa Eruption, its hot clouds did not get beyond the distance of 16 kilometers from the crater. Obviously, there are other causes that make the hot clouds of Krakatoa soared so far.
How can hot clouds spread over the surface of seawater? The answer is found in the Armin Freundt experiment (2001) at the Geomar Research Center for Marine Geosciences in the city of Kiel (Germany). When the hot clouds that first spread on land began to enter the sea, there was a steamy explosion followed by the separation of grains of sand and rock (whose mass was larger than water) with fine grains of dust (whose density was smaller than water). The hot cloud section with larger density sinks to the seafloor but continues as a 'hot underwater cloud' which then turns into turbidite currents. This movement created a major upheaval in the ocean water column above it, which then spread as a tsunami. While the hot part of the cloud that the smaller density still rode above sea level to a certain distance before losing all its speed and then soaring into the air as volcanic ash.
Lesson Ahead
Based on this enlightenment, we can now drill deeper into the mystery that has enveloped the Burning Ash of Katimbang event. Apparently, the incident is the result of a combination of Krakatoa lateral eruption with the spreading of hot clouds on the surface of the Sunda Strait. As the island of Krakatoa began to enter the phase of destruction as the eruption after the great eruption, the structure of the slopes increasingly weakened.
At one point, the slope of the mountain was so weak that the fresh magma that was searching for an outlet in it suddenly encountered fresh air. There was a lateral eruption that led northward. In the beginning, the speed of the gas column and the thrashed volcanic material may exceed the speed of sound, but gradually slow down. After sliding 15 to 20 kilometers from the mountain, the volcanic material column that has slowed down and transformed into a hot cloud. Some of the hot clouds sank to the bottom of the Sunda Strait (which is between 20 and 60 meters deep) and turned into a 'hot underwater cloud' that ran for several miles. While others remain floating on the surface of the Sunda Strait, it is still at high temperatures (up to about 500 degrees Celsius) and is still roaring at a relatively high speed for human size (probably around 100 km / h). This is what skyrocketed to about 28 kilometers later and created hell in Katimbang.
One valuable lesson to be learned from the Burning Ash of Katimbang is, do not overlook the marine volcano even though it is a distant 'distance' for our size. Because when it erupts, especially if the eruption is a catastrophic eruption that destroys the body of the mountain, the potential for the formation of deadly tsunamis and events similar to the Burning Ash of Katimbang is very large. This is a valuable lesson learned by the world of modern volcanism from the 1883 eruption of Krakatau. Thank's!!!
BEST REGARDS @irza
Reference :
https://en.wikipedia.org/wiki/Krakatoa
https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa
https://en.wikipedia.org/wiki/Sunda_Strait
https://en.wikipedia.org/wiki/Krakatoa:_The_Last_Days
http://www.drgeorgepc.com/Tsunami1883Krakatoa.html
https://www.livescience.com/28186-krakatoa.html
http://volcano.oregonstate.edu/describe-1883-eruption-krakatau
http://mentalfloss.com/article/67852/10-facts-about-krakatoas-1883-eruption