One hundred and thirty-six years ago yesterday, the world was shaken by what may well have been the biggest natural explosion in history. The bang, or rather series of bangs, was heard in Perth in western Australia, nearly 2,000 miles from their source. They were also heard on Rodriguez Island in the Indian Ocean, which was 3,000 miles away and their effects were felt all around the world.
The cause of the explosions was the eruption of the three volcanic cones on the island of Krakatoa, which is situated in the Sunda Straits between the Indonesian islands of Sumatra to the north and Java to the south. The area is part of the "Pacific Ring of Fire," a series of more than 400 volcanoes in a horseshoe shape in the northern Pacific Ocean.
The earth's crust has always been volatile in this area and, sometime in pre-history, there had been a massive eruption that resulted in the formation of a volcanic caldera and the group of islands that included Krakatoa.
We have no idea how many times Krakatoa has erupted. Certainly the 1883 eruption was not the first; in fact, we have documentary evidence of earlier ones. The Javanese Book of Kings, an ancient history of the kings of part of Indonesia, records an eruption in the Sunda Strait in the year 416 AD. The book says a thunderous noise was followed by a "great glowing fire, which reached to the sky." This was accompanied by the ground shaking, heavy rain and a great noise as the mountain "burst into pieces and sank into the earth." The report goes on to talk of a tsunami that inundated the land and swept away many of the inhabitants.
Fast forward 119 years and we come to 535-536 when crops failed globally, thousands died of famine and chroniclers as far away as Ireland recorded the sky full of dust or ash. This was thought to be due to a massive eruption, perhaps of Krakatoa. It has been suggested that the Javanese got their dates wrong and the eruption they recorded in 416 was in fact this one.
It's not possible now to know whether it was two separate eruptions or a mistake in the records, certainly the geological record doesn't seem to indicate anything in the 5th century. What is known is that the volcano on Krakatoa was known locally as "Fire Mountain" and there were at least four eruptions at 100-year intervals from around the year 850 to 1150. These were followed by another in 1320 and one more in 1530.
In 1679, a Dutch mining engineer named Johann Wilhelm Vogel was on board a ship that passed by the island. He described Krakatoa at the time as being completely covered in healthy green vegetation. Eighteen months later, he made the return journey and, to his astonishment, saw that the island was now completely black with burnt-out plants and trees, while columns of flames and smoke could be seen venting into the sky at four separate locations.
A hundred years after this, in 1780, the British warships HMS Resolution and HMS Discovery called at Krakatoa. They discovered fresh water, hot springs and luxuriant vegetation. There was even a friendly native population living there.
When the sloop of war USS Peacock called at the island in 1832, they found it difficult to land due to heavy surf and an extensive coral growth extending well out from the island. The water was exceptionally clear with masses of coral growths and, on the Eastern side, many hot springs as much as 150 yards from the shore. The island itself was again covered in greenery, including wild mango and orange trees that were full of monkeys and several species of birds.
Fifty years later, the scene changed. The area had been subject to increasingly frequent earthquakes for some years but, on May 20, 1883, the most northerly of the island's three volcanoes started sending columns of steam and ash into the upper atmosphere. For two weeks, the island grumbled, but then the activity died away for a period.
On June 16, there were several loud explosions and the island was obscured by a thick, black cloud of smoke for the next five days. When it cleared, new vents could be seen and a Dutch engineer who was brave, or foolish, enough to land reported finding 11 new vents and three major columns of ash.
The seismic activity was causing high tides, ongoing earthquakes and masses of pumice were seen. This activity went on through July and much of August but then, on the 25th, it intensified until it became almost continuous and the next day Krakatoa was sending up a black cloud of ash and pumice almost 20 miles high.
That evening, a small tidal wave hit the shores of the Sunda Strait and the eruption continued through the night, culminating early next morning. At 5:30 a.m., there was a tremendous explosion that sent a tsunami nearly 90 feet high racing north toward Sumatra. An hour later, the second explosion sent a bigger tsunami east and west, but it was the third bang, at about 10 a.m., that was the loudest and biggest. It's been estimated that it released an energy blast four times more powerful than the biggest nuclear weapon ever detonated and it sent a pressure wave racing at 675 mph all around the world three and a half times. This was followed by a fourth explosion and, when the smoke cleared, only 30 percent of Krakatoa remained.
It's not known how many people were killed by the eruption. Some ships vanished without trace, as did the three thousand people living on the nearby island of Sebesi. The town of Merak was wiped from the map by a tsunami that was estimated to be 150 feet high and, all told, the Dutch authorities, who ruled the area at the time, gave an official death toll of 36,417. This was certainly a large understatement and scientists estimate the actual figure may well have been more than 100,000.
As I said at the beginning of this piece, Krakatoa exploded 136 years ago. Could it happen again? The answer to that has to be perhaps. The island's volcanoes have erupted regularly for hundreds of years, the 1883 one was the biggest in recorded history but it may not have been the last. Should we be worried that if there is another eruption it will be as bad? There's no way of knowing. Temperatures dropped in the Northern Hemisphere for the following two years, there were brilliant red sunsets half way around the world for months, crops failed, rainfall increased and weather patterns were chaotic. All that was from an eruption 10,000 miles away; perhaps we should remember there are 1,500 other active volcanoes in the world, 169 of them right here in the United States.
Derek Coleman is a part-time writer who is a native of England and who now lives in Hurricane, W.Va. He can be reached at firstname.lastname@example.org.