1883 eruption of Krakatoa

In 1883 the volcanic island of Krakatoa, in the Sunda Strait between Java and Sumatra in what was then the Dutch East Indies, erupted for several months before tearing itself apart on 27 August. The climactic explosions destroyed most of the island and raised tsunamis that swept the surrounding coasts, killing at least 36,417 people according to the official count. The blast produced the loudest sound ever recorded, and its ash and gases altered skies and weather around the world.

Earthquakes had shaken the region for years before the eruption. Activity began on 20 May 1883 at Perboewatan, the most northerly of Krakatoa's three volcanic cones, throwing ash about six kilometres into the air; the explosions rattled windows in Batavia, modern Jakarta, some 160 kilometres away. After a lull, eruptions grew stronger again from mid-June, new vents opened, and by early August a Dutch survey officer, Captain H. J. G. Ferzenaar, found the island buried in ash, its vegetation destroyed and more than a dozen vents active. He advised against any further landings.

The eruption entered its final phase in the early afternoon of 26 August, when a black cloud rose some 27 kilometres and explosions became almost continuous. Through the night ash and hot pumice fell on ships nearby, and small waves struck the shores of Java and Sumatra. On the morning of 27 August a series of enormous explosions followed. The third and largest, at about 10:02 a.m., was heard 3,110 kilometres away in Perth, Australia, and on the island of Rodrigues near Mauritius, 4,800 kilometres away, where people took it for distant gunfire. Its pressure wave was recorded on barographs around the world seven times over five days as it travelled back and forth across the globe. Shortly afterwards much of the island, including half of the Rakata cone, collapsed into the emptied magma chamber.

The worst destruction came from the sea. Waves estimated at more than 30 metres high in places swept the coasts of the Sunda Strait, washing away villages and forests. The town of Merak was destroyed, and the steamer Loudon, anchored off Telok Betong in Sumatra, rode over a wave that then obliterated the town. Pyroclastic flows of hot gas and ash raced some 40 kilometres across the sea to Sumatra, where they burned villages; around Ketimbang a fall of hot ash killed about 1,000 people. All 3,000 inhabitants of the nearby island of Sebesi died. Bodies drifted on rafts of pumice across the Indian Ocean, some reaching the coast of East Africa up to a year later.

The eruption threw enormous amounts of ash and sulphur dioxide into the stratosphere. In the following year average summer temperatures in the Northern Hemisphere fell by about 0.4 °C. For months, sunsets around the world glowed so red that fire brigades in New York and other American towns turned out to fight blazes that did not exist, and the moon was sometimes seen as blue or green. Observers tracking the drifting haze identified a fast high-altitude current, an early recognition of what is now called the jet stream, and some have suggested that the red sky in Edvard Munch's painting The Scream recalls the Krakatoa sunsets over Norway. Thanks to telegraph cables, news of the disaster travelled faster than that of any earlier natural event.

Only the southern third of Krakatoa survived, leaving a sheer cliff on Rakata, while deposits of volcanic debris reshaped the surrounding seabed. Part of the devastated land in Banten, on Java, was never resettled and is now Ujung Kulon National Park. Later surveys detected signs of magma beneath the sea at the site where a new volcano, Anak Krakatoa, eventually rose.

Our 1880 map shows the Dutch East Indies, whose islands of Java and Sumatra bore the brunt of the disaster, in what is now Indonesia.