Krakatoa - Volcanic Blast Felt Around The World
In 1883 the Indonesian island of Krakatoa was blown apart by one of history's worst volcanic eruptions and after effects were felt years later.
Volcanoes have been part of the planet’s natural geology since the dawn of time, re-shaping mountain ranges and shifting entire land masses. They’ve destroyed cities and civilizations and blown apart whole islands.
Active volcanoes are restricted to certain regions of the earth. An unbroken line of them run through the Pacific Ocean and is called the “Ring of Fire”. Some are active, others lie dormant or extinct. The Caribbean and Mediterranean seas are dotted with just as many active or extinct volcanoes. Everyone is familiar with Mount Vesuvius and its cataclysmic destruction of the ancient city of Pompeii. Mount St. Helen’s sudden eruption in 1980 won’t soon be forgotten. Yet despite the destructive force of these two volcanoes, there is another one that, when it erupted in 1883, unleashed one of the most catastrophic volcanic explosions in history. Its name is Krakatoa.
Krakatoa, also called Krakatau, is located in the Sunda strait between the islands of Java and Sumatra, Indonesia. Geologists believe that over the last million years, repeated volcanic eruptions of cinder, ash and magma on a single large island eventually created four smaller ones known as Pulau Sertung, Lang, Polish Hat and Rakata. A minor eruption on one of the islands was recorded in 1680. For the next 200 years all was quiet. Then, on May 20, 1883, Krakatoa came violently alive, spewing thick ash clouds 6 miles into the atmosphere. Repeated explosions were heard over 100 miles away. Then after two weeks, activity all but ceased. But by mid-June eruptions resumed. They intensified and by August 26 a series of even more violent explosions occurred.
By mid-afternoon plumes of black ash clouds rose 17 miles above Krakatoa. At 10AM on August 27th one final catastrophic explosion split wide the island. The blast was heard as far away as Australia, a distance of over 2000 miles. Atmospheric pressure waves were recorded world-wide and over a period of 12 days. Ash continued to rise into the atmosphere to a height of over 50 miles. Regions in an 80 kilometre radius were cast into 60 hours of darkness. But the worst was yet to come.
The blast displaced and collapsed two thirds of Krakatoa island. When this happened the ocean literally sank in on itself and a series of massive tsunami (tidal waves) were generated. They smashed into the coastal lowlands of Java and Sumatra on the opposite side of Sunda Straight. An estimated 36,000 people were killed. Chunks of coral and newly formed pumice boulders, some weighing as much as 600 tons, were hurled ashore, crushing everything in their path. Smaller tidal waves were recorded as far away as Hawaii and South America.
There were many more long-lasting after-effects of the Krakatoa eruption. Blue and green suns were the norm as fine ash and other debris were pumped into the stratosphere, circling the equator for 13 days. Three months later vivid red sunsets were seen on the eastern seaboard of North America. This phenomena continued for 3 years. Huge pieces of pumice that were ejected by the blast were still floating on the ocean two years later, travelling as far as Melanesia. Scientists estimate that the volcanic dust veil created lowered global temperatures by close to 1.2 degrees centigrade. It took 5 years for the temperatures to return to normal.
The new and smaller island that was created was re-named Anak Krakatoa (child of Krakatoa) and remained dormant until 1927 when a series of 23,000 tremors were registered. A period of inactivity lasted until 1953 when pyroclastic eruptions (ash explosions) occurred, destroying 90% of the ecosystems on Panjang and Sertung islands. Lava began to flow in the 1960’s and over the next 20 years created new beach and solid geology once again. By the 1990’s the Anak had grown to a height of 300 meters and her radius spread to 4 kilometres.
What are the chances of Krakatoa erupting with the same catastrophic force as it did in 1883? Scientists agree that most volcanoes are difficult to predict. Anak Krakatoa is no different. They do agree that while Anak has not grown to nearly the size of her formidable parent, she is not a volcano to be taken lightly. Within the bowls of the earth, the magma chambers continue to bubble and fill. Eventually enough pressure will build to produce another possibly devastating blast felt around the world.