Krakatoa, 1883: The Explosion Heard 4,800 km Away

On 27 August 1883, the Indonesian volcano Krakatoa exploded with a sound so loud it was heard almost 4,800 kilometres away — perhaps the loudest noise in recorded history.

The blast and the tsunamis it generated killed roughly 36,000 people and sent a pressure wave around the planet several times.

Play video: POV: You hear a volcano 4,800 km away · Krakatoa 1883Ep. 6 · 1883 — You hear a volcano 4,800 km away · Krakatoa 1883Time & Space

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Ep. 6 · 1883

POV: You hear a volcano 4,800 km away · Krakatoa 1883

You hear a volcano 4,800 km away · Krakatoa 1883

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What happened

Krakatoa sat in the Sunda Strait between Java and Sumatra. After months of smaller activity, a series of cataclysmic explosions on 26–27 August 1883 destroyed most of the island. The climactic blast was heard on Rodrigues Island in the Indian Ocean, nearly 4,800 km away — people there thought they were hearing distant gunfire.

The science: sound, pressure and the sea

A sound audible thousands of kilometres away is almost beyond imagining; near the volcano the pressure was strong enough to rupture eardrums and damage ships. Barometers worldwide recorded the atmospheric shockwave circling the Earth multiple times. But most deaths came not from the sound — they came from the sea. Collapsing parts of the volcano displaced enormous volumes of water, sending tsunamis more than 30 metres high crashing into the coasts of Java and Sumatra.

A sky that changed colour

Ash and gas from Krakatoa spread worldwide, producing vivid red sunsets and a measurable dip in global temperatures over the following year. Some scholars link the lurid sky in Edvard Munch’s The Scream to these afterglows.