Article
When the World Heard a Sound: The 1883 Krakatoa Eruption
On August 27, 1883, at 10:02 in the morning, a volcanic island between Java and Sumatra blew itself apart with a sound louder than anything ever recorded — and almost certainly louder than anything a human ear could survive at close range. The explosion was heard 4,800 km away on the island of Rodrigues in the Indian Ocean, where it was mistaken for cannon fire from a nearby ship. In Perth, Australia, 3,100 km distant, it registered clearly. The acoustic pressure wave circled the globe not once, but more than three times. [1][2]
This is the story not just of an eruption, but of the first global natural disaster captured by science, art, and telegraphy — a moment when the world realized it was connected in ways it hadn't understood.
The mountain that woke up
The volcano on the uninhabited island of Krakatoa (or Krakatau, in Indonesian) had been quiet for at least two centuries when, on 20 May 1883, it began to stir. Steam venting and Strombolian eruptions — mild, explosive bursts — started from the northernmost cone, Perboewatan. Ash reached an estimated 6 km into the air, and the explosions rattled windows and doors 160 km away in Batavia (modern-day Jakarta). [1][3]
A sightseeing party that landed on the island on 26 May found it covered in fine white dust, with Perboewatan erupting every five to ten minutes. They also discovered that a crater roughly 900 meters in diameter had formed. The eruptions then quietened — but not for long. [1]
By mid-June the violence returned. A new vent opened between Perboewatan and the volcano's central cone, Danan. Soon there were three major ash columns and, by early August, a Dutch engineer named Captain Ferzenaar counted steam plumes from at least eleven separate vents. The vegetation on the island was gone — only tree stumps remained under a layer of ash half a meter thick. He advised against any further landings. Good advice. [1][3]
The day the mountain fell
On 26 August, the eruption entered its climactic phase. At 1:00 p.m., a black ash cloud rose 27 km high. By 5:00 p.m., the explosions were audible across all of Java. Waves began battering the coasts. Ships within 20 km of the volcano reported heavy ash fall and pieces of hot pumice up to 10 cm in diameter landing on their decks. [1]
Then came the morning of 27 August.
At 5:30 a.m., the first enormous explosion blasted Perboewatan apart, triggering a tsunami aimed at the Sumatran coast. At 6:44 a.m., Danan exploded, sending another tsunami east and west. Then, at 10:02 a.m., came the third and largest blast — so violent that it blew the northern two-thirds of the island into the sea. [1]
The sound has been calculated at 180 dB SPL at 160 km from the volcano. [4] For reference: 150 dB will rupture eardrums. A Saturn V rocket at launch measured about 200 dB at the pad. Krakatoa's final explosion was powerful enough that its pressure wave was recorded by barometers in Great Britain and America. The instruments in London showed the wave passing — and then, several hours later, passing again on its second circumnavigation. [1][5]
The official report published by the Royal Society noted that "the wave travelled more than three times round the world" and that "the barometric records at 50 stations in Europe and America show the passage of the wave." [2]
Tsunamis that rewrote coastlines
As dramatic as the sound was, it was not the deadliest part of the eruption. When the northern two-thirds of Krakatoa collapsed into the sea, it displaced an enormous volume of water, generating a series of tsunamis whose largest wave, recorded in the Indonesian province of Banten, was estimated at 41 meters (135 feet) high. [5]
The waves destroyed 165 coastal towns and villages. Of the estimated 36,417 people killed by the eruption, more than 34,000 died from the tsunamis — nearly 95%. Bodies washed up along the shorelines for weeks afterward. A telegram from the town of Serang reported grimly: "All gone. Plenty lives lost." [1][5]
The tsunamis traveled far beyond Indonesia. The waves were recorded as far away as Hawaii and the coast of South America. [5]
The sky turned red — and stayed that way
Krakatoa ejected an estimated 20 million tons of sulfur into the stratosphere, along with billions of tonnes of ash and debris. The ash cloud rose 80 km into the sky, blanketed 800,000 square kilometers of the surrounding area, and plunged the region into darkness for two and a half days. [5]
The stratospheric veil then spread. It threaded slowly westward around the equator, and by late October 1883, most of the world was seeing the effects. Sunsets turned lurid shades of green, blue, copper, and magenta. In New York, the sky turned such a deep red one evening that fire engines were called out to extinguish what appeared to be a massive fire in the distance. [6]
Gerard Manley Hopkins, the English poet, watched the skies over Lancashire with growing fascination. In a letter to the journal Nature published in January 1884, he described what he saw:
"The red was first noticed 45º above the horizon, and spokes or beams could be seen in it, compared by one beholder to a man's open hand... A great sheet of heavy dark cloud, with a reefed or puckered make, drew off the west in the course of the pageant: the edge of this and the smaller pellets of cloud that filed across the bright field of the sundown caught a livid green." [7]
The Royal Society of London commissioned the landscape painter William Ascroft to record the sunsets systematically. Ascroft produced hundreds of color sketches of the skies over Chelsea and Chiswick, capturing a phenomenon that pre-photography science had no other way to preserve. His paintings — some of which show the sky in bands of fiery orange and deep crimson — remain one of the most complete visual records of a volcanic atmospheric event before the 20th century. [8]
The effects even left a mark on art history. Edvard Munch's The Scream (1893), with its swirling red sky, is widely believed to have been influenced by the Krakatoa sunsets. Munch wrote in his diary about walking with friends as the sun descended through the haze: "it was as if a flaming sword of blood slashed open the canopy of heaven." [9]
Climate and the long aftermath
The eruption had measurable global climate effects. The stratospheric aerosol layer — sulfur compounds reflecting sunlight back into space — caused global temperatures to drop by an estimated 0.5°C to 1.2°C. The cooling lasted roughly five years, with temperatures not returning to normal until 1888. [5][10]
The scientific response was equally global. The Dutch government appointed the Dutch Scientific Commission in October 1883, led by geologist Rogier Verbeek, who published his landmark report Krakatau in 1884 — the definitive geological account of the eruption, based on detailed measurement of the ejected material and the island's collapse. [11] The British Royal Society followed with its own committee in January 1884, chaired by Thomas Henry Huxley (Darwin's great defender), which published a comprehensive report in 1888 collecting observations and measurements from around the world. [2][12]
It was arguably the first global scientific collaboration on a natural disaster — organized not by telegraphy's speed, but by the sheer spectacle that no one anywhere could ignore.
What's left
Today, a new volcano — Anak Krakatau, "Child of Krakatoa" — rises from the same caldera, first emerging above the sea in 1928. It has been intermittently active ever since, including a major eruption and collapse in December 2018 that generated a deadly tsunami. [1] The sound of 1883 is still the loudest ever measured. The sunsets have faded, but the ash layers in ice cores tell the story. And somewhere in the archives of the Science Museum Group in London sit Ascroft's watercolors — a painter's record of a sky that, for a few months, looked like no sky anyone had ever seen before.
Sources:
[1] Wikipedia, "1883 eruption of Krakatoa" — fetched this session; primary source for eruption sequence, sound, death toll. https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa
[2] The Royal Society, "The Eruption of Krakatoa, and Subsequent Phenomena" (1888) — the definitive scientific report, referenced in Wikipedia and the BRANCH article. Summary via Public Domain Review.
[3] Monique R. Morgan, "The Eruption of Krakatoa (also known as Krakatau) in 1883", BRANCH: Britain, Representation and Nineteenth-Century History. https://branchcollective.org/?ps_articles=monique-morgan-the-eruption-of-krakatoa-also-known-as-krakatau-in-1883
[4] Self, Stephen (1992). "Krakatau revisited: The course of events and interpretation of the 1883 eruption." GeoJournal 28(2): 109. — cited in Wikipedia for sound intensity calculation. doi:10.1007/BF00177223
[5] NOAA National Centers for Environmental Information, "On This Day: Historic Krakatau Eruption of 1883" — fetched this session; source for ash cloud extent, temperature drop, tsunami heights. https://www.ncei.noaa.gov/news/day-historic-krakatau-eruption-1883
[6] Racing Nellie Bly, "Dramatic Skies From Victorian Era Krakatoa Eruption Touched People Worldwide" — referenced the New York fire engine anecdote. https://racingnelliebly.com/weirdscience/victorian-era-krakatoa-eruption/
[7] Gerard Manley Hopkins, "The Remarkable Sunsets", Nature 29 (3 January 1884), pp. 222-23 — full text excerpted in the Public Domain Review essay fetched this session.
[8] Richard Hamblyn, "The Krakatoa Sunsets", The Public Domain Review (28 May 2012) — fetched this session; source for Ascroft commission and Hopkins' observations. https://publicdomainreview.org/essay/the-krakatoa-sunsets/
[9] Wikipedia, "The Scream" — referenced for Munch's connection to the Krakatoa sunsets, corroborated by multiple sources including the Public Domain Review and Hyperallergic.
[10] ResearchGate, "Climate effects of the 1883 Krakatoa eruption: Historical and present perspectives" — referenced for the global temperature drop. https://www.researchgate.net/profile/Nathalie-Schaller/publication/255700466
[11] Rogier Verbeek (1884/1885), Krakatau — the definitive geological monograph commissioned by the Governor-General of the Dutch East Indies. Referenced via Wikipedia and Linda Hall Library. https://en.wikipedia.org/wiki/Rogier_Verbeek
[12] Linda Hall Library, "Rogier Verbeek — Scientist of the Day" — for the Royal Society committee's reliance on Verbeek's work. https://www.lindahall.org/about/news/scientist-of-the-day/rogier-verbeek/