The 1883 eruption of Krakatoa

Lore & Background

The 1883 eruption of Krakatoa, located in the Sunda Strait within the Dutch East Indies (modern-day Indonesia), began on 19 May and continued until 21 October, lasting over five months. The island featured three main cones: Perboewatan, Danan, and Rakata. Early Strombolian activity from Perboewatan sent ash to 6 km, with explosions heard 160 km away in Batavia. By June, new vents appeared between Perboewatan and Danan, and eruptions intensified through July. On 25 August, the eruption entered its climactic phase, with a black ash cloud reaching 27 km high by 26 August. The climax occurred on 27 August with eleven enormous explosions, the third at 10:02 a.m. being the loudest-known sound in history, heard 3,110 km away in Perth and 4,800 km away near Mauritius. The acoustic pressure wave circled the globe more than three times. The explosion destroyed over 70% of the island, collapsing it into a caldera. At least 36,417 deaths resulted from the eruption and its tsunamis. Additional seismic activity was reported until February 1884, though later reports were dismissed by investigator Rogier Verbeek. The eruption had a Volcanic Explosivity Index of 6, making it one of the deadliest volcanic events in recorded history.

Reader's Guide

Its climactic explosion on 27 August produced the loudest sound ever recorded, heard across thousands of kilometers, and generated a pressure wave that circled the Earth multiple times. The eruption destroyed over 70% of the island and triggered massive tsunamis that devastated coastal communities, causing tens of thousands of deaths. The event provided crucial data for understanding volcanic explosivity, pyroclastic flows, and tsunami generation. The eruption's global effects, including atmospheric dust and pressure waves, influenced scientific study of volcanic impacts on climate and sound propagation. Rogier Verbeek's subsequent investigation dismissed later seismic reports, shaping the historical record. Krakatoa's eruption remains a benchmark for measuring volcanic power and a cautionary example of nature's destructive capacity.

Did You Know?

• The third explosion on 27 August at 10:02 a.m. is the loudest-known sound in history.
• The pressure wave circled the globe more than three times.
• The energy released was estimated at about 200 megatonnes of TNT, roughly four times as powerful as the Tsar Bomba.

The Engine Beneath the Island

For centuries, Mount Tambora sat in silence on the island of Sumbawa, its magma chamber slowly cooling and crystallizing at depths between 1.5 and 4.5 kilometers. That quiet period, however, was far from inert. On the climactic evening of April 10, three eruption plumes rose and merged, transforming the entire mountain into what witnesses described as a flowing mass of liquid fire. The blast hurled an estimated 41 cubic kilometers of pyroclastic trachyandesite—roughly ten billion tonnes—into the sky.

A Detonation Heard Across the Archipelago

The acoustic signature of Tambora's eruption was staggering in its reach. The eruption's physical reach was equally vast. In Batavia, a distinct nitrous odor hung in the air, and heavy rain streaked with volcanic tephra fell for days, finally clearing between April 11 and 17.

Poisoning the Stratosphere

The eruption column punched through the troposphere and into the stratosphere, reaching altitudes above 43 kilometers. While coarser ash particles fell back to Earth within one or two weeks, the finest particles became trapped at heights between 10 and 30 kilometers, where they persisted for months and even years. Driven by longitudinal winds, these microscopic fragments circled the entire globe, scattering sunlight and triggering a cascade of optical and climatic effects. The glow typically blazed orange or red along the horizon, fading into purple or pink higher in the sky. The resulting climate disruption triggered extreme weather events and catastrophic harvest failures across multiple continents, a pattern of interacting climate forcings that has not been replicated by any other large volcanic eruption since the early Stone Age.

Devastation and the Long Silence

The human and ecological toll was immense. Every trace of vegetation on Sumbawa was obliterated, and uprooted trees tangled with pumice ash were swept into the sea, forming floating rafts up to five kilometers across. A violent whirlwind struck the village of Saugur, now called Sanggar, flattening nearly every structure and hurling large trees into the air.

Common Misconceptions (Editorial)

Some people believe the loudest sound from the eruption occurred at the very start or was a single, continuous blast, but the facts show the loudest-known sound in history was the third explosion at 10:02 a.m. on 27 August. Others think the eruption destroyed the entire island completely, but the records indicate it destroyed over 70% of it, with the remaining portion collapsing into a caldera.

Why It Matters (Editorial)

The 1883 eruption of Krakatoa endures as a stark reminder of nature’s capacity for instantaneous, planetary-scale devastation. Its thunderous finale, still the loudest sound ever recorded, and the global pressure wave it generated, underscore how geological events can transcend borders and reshape human understanding of risk and resilience.