It approached the maximum possible intensity of 194 decibels and exceeded the Hiroshima bomb thousands of times
At 10:02 a.m. on August 27, 1883, The eruption of the Krakatoa volcano in Indonesia wiped out an island and caused tsunamis that created waves 46 meters high and that they arrived until South Africa. It was as a consequence of this eruption that the the most powerful sound yet recorded.
Krakatoa was a small uninhabited island halfway between Java and Sumatra in Indonesia. It rose 838 meters above sea level and had last been volcanically active in 1680 before it began to roar again in 1883. The eruption that year had a power comparable to a 200-megaton bomb (the Hiroshima explosion didn’t even reach 1).reports the Natural History Museum, and it had a far-reaching impact on people and the environment.
In terms of lives lost, Krakatoa (with 36,000 victims) was the second deadliest eruption in modern history, surpassed by the 1815 eruption at Tambora (also in Indonesia), which claimed at least 60,000 lives.
These explosions carry extreme fluctuation in air pressuresomething that, within certain ranges, is perceived as sound.
The chronicles of the time collect testimonies that ensure that the detonation could be heard in the Andaman and Nicobar islands, in India, more than 2,000 kilometers away; in New Guinea and Australia, more than 3,200 kilometers away, and even on islands in the Indian Ocean located almost 5,000 kilometers away.
A barometer reading at a gasworks located 160 kilometers from Krakatoa on the fateful day of its violent eruption recorded a sound of 172 decibels., an index that, with a sudden increase in pressure, bursts the eardrums even at that distance. According to experts, with 120 decibels and even less, the ear can already suffer damage and the human threshold for pain is 130 decibels. From there, every 10 decibel increase above that is like the noise doubled.
It must be taken into account that the sound of fireworks at close range usually registers 145 decibels, and a fighter taking off, around 150 if it is also close. The loudest sound physically possible in air is 194 decibels, slightly more than the 180 recorded next to a space rocket taking off.
During the Krakatoa eruption, the burst of pressurized air it also broke the eardrums of the sailors of a ship that was sailing 64 kilometers from the island.
“So violent are the explosions that the eardrums of more than half my crew have been shattered,” reported the British ship’s captain Norham Castle. “My last thoughts are with my dear wife. I am convinced that Judgment Day has come, ”he added.
That same shock wave continued to move across the planet, getting softer the farther it traveled, but it took time to die down completely. According to Brüel & Kjær, still it could be heard as if it were a cannon shot at a distance of 4,800 kilometers from Krakatoa.The pressure wave circled the globe three times in each direction., with shock waves colliding in various parts of the planet and creating additional pressure spikes. “The great wave of air”, as it became known, continued to travel around the planet for some time and after it dropped below the hearing threshold, and thus ended the loudest sound in history.
The loudest sound since Krakatoa is believed to have been the Tonga eruption, which occurred in January 2022., whose sonic boom was heard throughout Alaska, located 6,200 kilometers away. Tonga also sent sound waves and tsunamis across the planet, with a pressure wave moving at more than 1,100 kilometers per hour and reaching an altitude of 450 kilometers, that is, above where the International Space Station is located.
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