The Sound So Loud, Enough to Circumnavigate the Earth Four Times

On Aug. 27, 1883, just after 10 a.m., the Krakatoa volcano in Indonesia erupted with the loudest sound in recorded history – a horrifying scream that carried sound waves four times around the earth and could be heard 4,800 km distant on the Indian Ocean island of Rodrigues.

This is comparable to Californians hearing a noise generated in New York. Rodrigues, like other remote locations, mistook the roar for artillery fire. People in western Australia, 2,000 km away, believed war had broken out.

Sailors on a British ship 65 km away had damaged eardrums; the captain felt Judgement Day had arrived.

In Batavia (now Jakarta), a gas works barometer soared to an equivalent of 172 decibels, indicating that the sound was several times louder than a jet engine even 100 miles away.

"This is astoundingly loud," writer Aatish Bhatia wrote in a Discover magazine essay, adding that the sound of a jet engine reaches 150 decibels. In all, the pressure waves from Krakatoa circled the globe three to four times in each direction. (Each city felt up to seven pressure spikes because they experienced shock waves traveling in opposite directions from the volcano.) Meanwhile, tidal stations as far away as India, England, and San Francisco measured a rise in ocean waves simultaneous with this air pulse, an effect that had never been seen before. It was a sound that could no longer be heard but that continued moving around the world, a phenomenon that people nicknamed “the great air-wave.”

According to an 1888 research by the Royal Society of Great Britain, the sound could be heard throughout nearly a thirteenth of the earth's surface.

The explosion's damage — equal to 10,000 Hiroshima-sized atomic bombs — making the Krakatoa eruption one of the worst natural catastrophes in history.

Over 36,400 people were killed by lava flows traveling at speeds of up to 100 km per hour and tsunamis reaching a height of 36 m and destroying 165 coastal communities.

Volcanic materials spewed into the sky filtered sunlight and created sunsets so bright that residents of New York, Connecticut, and other locations phoned the fire department, fearful of a fire breaking out. The average global temperature decreased by 1.2 degrees Celsius in the year after the eruption, and the globe remained unusually chilly for around five more years.

Krakatoa was mostly destroyed in the aftermath of the explosion. In 1927, a volcanic island dubbed Anak Krakatoa (child of Krakatoa) developed from the crater created by the massive explosion. It is a dormant volcano. In December 2018, an eruption resulted in a tsunami that killed over 400 people.

Source: 

Sheehan, Daniel Patrick. “The Loudest Sound In History: Krakatoa Erupted On This Date 136 Years Ago - The Morning Call.” Mcall.com, Www.mcall.com, 27 August. 2019, https://www.mcall.com/news/local/mc-nws-krakatoa-anniversary-20190827-udxuiu2zmzf7xpubkmg6uju3pm-story.html.

Bhatia, Aatish. “The Sound So Loud That It Circled the Earth Four Times - Issue 38: Noise - Nautilus.” Nautilus, Nautil.us, 14 July. 2016, https://nautil.us/issue/38/noise/the-sound-so-loud-that-it-circled-the-earth-four-times.