How Loud Was the Krakatoa Eruption? The Loudest Sound in Modern History

The 1883 Krakatoa eruption registered an estimated 310 decibels at 100 miles away and was heard clearly in Perth, Australia — 3,110 miles from the volcano. It's the loudest sound in recorded human history. For context: a jet engine at takeoff is 140 dB. Krakatoa was about 170 dB louder, which (because dB is logarithmic) is roughly 100 quintillion times more sound energy.

How loud is 310 dB?

The decibel scale is logarithmic. Every 10 dB means 10x the acoustic intensity. So 310 dB is not "twice as loud as 155 dB" — it's unimaginably louder.

The theoretical maximum for a sound wave in air at sea level is about 194 dB. Above that, the compressions create a vacuum — not a sound wave but a shock wave. Krakatoa broke physics as we normally understand it because the energy output was so extreme it behaved like a different category of phenomenon.

How far it was heard

Accounts from 1883 confirm the sound was clearly audible at these distances:

100 miles — ruptured eardrums on ships in the Sunda Strait.
1,930 miles — heard in Diego Garcia (Indian Ocean) as "artillery fire."
3,110 miles — heard in Perth, Australia and described as "cannon fire."
4,800 km — faint audible pulse in Mauritius.

The pressure wave circled the Earth 4 times over the next 5 days, registered on every barograph on the planet.

The physical effects

People within 40 miles of Krakatoa had ruptured eardrums. Sailors reported their ships shaking violently. A tsunami up to 37 meters high was triggered by the blast — not by the eruption itself, but by the collapse of the volcano's cone into the sea.

Roughly 36,000 people died, most from the tsunami. The explosion itself ejected 25 cubic kilometers of rock and ash. Ash darkened skies globally for months and lowered average global temperatures by 0.4°C for the following year.

Energy equivalent

Krakatoa released the energy of about 200 megatons of TNT — 13,000 times the Hiroshima bomb. All of that went off in a matter of minutes.

Only one observed event in human history comes close: the 1815 Mount Tambora eruption (ranked higher on the Volcanic Explosivity Index, but with less dramatic acoustic signatures due to different geography).

What came after

Sunsets globally turned blood-red for 3 years. Ash high in the atmosphere scattered sunlight. London's sunsets in 1883-1884 are thought to be the inspiration for Edvard Munch's The Scream — the sky in that painting matches published descriptions from the period.

Temperatures across the Northern Hemisphere dropped enough that 1884 was nicknamed "the year without a summer" in parts of Europe. Crop failures followed.

Could it happen again?

Yes. Krakatoa itself has rebuilt — Anak Krakatau ("Child of Krakatoa") emerged from the sea in 1927 and collapsed spectacularly in 2018. But the 1883 event was an unusually large VEI 6 eruption, and nothing on the planet right now is ready to go at that scale.

Yellowstone, Campi Flegrei, and Taupo are capable of VEI 7 or 8 eruptions. They'd be substantially larger than Krakatoa. Read our breakdown of the Yellowstone scenario.

For comparison

The 2022 Hunga Tonga eruption was the loudest modern event, with pressure waves circling the globe. It was still roughly 100x less energetic than Krakatoa.

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