The British cargo ship Norham Castle, built in Glasgow, was launched in 1869 as a tea clipper for the trade with China. Clipper ships, sleek and three-masted, were designed for speed. Their production took off in the 1840s because of a growing demand for faster delivery of tea from China.
The Norham Castle transported tea and eventually mixed cargoes to places including Australia and New Zealand. In 1883 she was sailing near the Sunda Strait, which is located between the Indonesian islands of Java and Sumatra. It just so happens that most of Indonesia’s more than 130 active volcanoes lie between Java and Sumatra, the most famous being the stratovolcano (the steepest and most deadly kind) known to Westerners as Krakatoa.
By the summer of 1883 seismic activity around Krakatoa had been intensifying for months, producing earthquakes, steam venting, and ash eruptions. The three peaks of Krakatoa served as an exit for a huge magma chamber beneath. There is some speculation that an earlier eruption had clogged the neck of one of the peaks, creating an incredible amount of pressure building up below the blockage. The volcano was overdue for a climax.
Around 1:00 p.m. on August 26, a volcanic eruption sent a cloud of gas and debris about 15 miles into the air. The eruption was continuous, with numerous explosions. Capt. W.J. Watson of the Irish merchant ship Charles Bal reported that the noise was like the continuous discharge of heavy artillery. The noise intensified and was accompanied by a hail of ash and pumice. Ash eventually blanketed everything within thousands of square miles, plunging the area into darkness that would last two and a half days.
Capt. Watson said that the intense blackness made it impossible to see to any distance. There was also a small tsunami on the shores of Java and Sumatra.
Early in the morning on August 27, a series of explosions began triggering more tsunamis. The third of these explosions was the most horrific, so violent that it was heard about 1,900 miles away in Western Australia – and about 3,000 miles away on the Indian Ocean island of Rodrigues. People there thought the blasts were cannon fire from a nearby ship.
The noise from this explosion is arguably the loudest sound ever recorded. The barometer at a gasworks in Batavia (now Jakarta), 100 miles from Krakatoa, registered a spike in pressure of over 2.5 inches of mercury, which converts to over 172 decibels, at 100 miles from the source. (For context, if you were operating a jackhammer you would be subject to 100 decibels.)
At above 194 decibels, sound waves stop traveling through the air and begin pushing the air along with them – and the resulting “wind,” or shock wave, can blow anything in its path to pieces. Closer to Krakatoa the sound was well over this limit.
The shock waves created by the Krakatoa eruption shattered windows and shook homes within a 100-mile radius of the volcano. The shock waves were so powerful that they were recorded by barometric stations around the globe.
The tsunamis created by the eruption proved most deadly. More than 36,000 people were swept out to sea in the series of tsunamis caused by the volcano’s collapse, which created a wall of water over 100 feet high that wiped out scores of coastal villages on Java and Sumatra. The tsunami carried the Dutch ship Berouw a mile inland, killing all 28 crew.
The eruptions also created pyroclastic flows – avalanches of lava, ash, and pumice. These flows scorched everything in their path, whether passing ships or coastal villages. Michael Bubb writes:
Of the 36,000 deaths, around 4,500 were attributed to the pyroclastic flows which would have arrived just after the tsunamis. Most likely the 4,500 who met their fate with the flows had reached higher ground or shelter to avoid the rushing water, only to be engulfed in fire and ash.
Unimaginable horror was unfolding on the Sunda islands.
This catastrophe marked a series of “firsts,” says geologist David Bressan. It was the first global catastrophe and the first news story to go around the world, thanks to modern communications.
As the Sunda Strait was and still is an important passage from the Indian Ocean to the Chinese Sea, news about the eruption and destruction of harbors and lighthouses in the area were of special interest to merchants, politicians, and the public in general…
Krakatoa was also the first scientifically well recorded and studied eruption of a volcano, from the very beginning to its disastrous ending.
The study of what was left of the former island of Krakatoa also spawned a new scientific discipline: disturbance ecology. Observations made at Krakatoa were valuable for understanding the colonization of devastated or newly formed terrain.
And what of the clipper Norham Castle? On Sunday, August 26, the vessel was at the eastern entrance of the Sunda Strait, along with another ship, the Sir Robert Sale. On Monday morning both vessels entered the Strait but because of blackened skies neither made much progress.
Capt. O. Sampson of the Norham Castle reported that Krakatoa “appeared to be alight with flickering flames rising behind a dense black cloud; at the same time balls of fire rested on the mastheads and extremities of the yardarms.”
In the wake of the devastating eruption, Capt. Sampson wrote in his official log:
I am writing this blind in pitch blackness. We are under a continual rain of pumice and dust. So violent are the explosions that the eardrums of over half my crew have been shattered. My last thoughts are with my dear wife. I am convinced the Day of Judgement has come.
By the morning of Tuesday, August 28, Krakatoa had gone silent. The volcanic island had almost entirely sunk, except for the southern third. The blackness of the sky was slowly beginning to lift. The Sir Robert Sale and the Norham Castle finally made it through the Strait.
