The 1883 eruption of Krakatoa was one of the deadliest natural disasters in history. It’s thought to have caused the deaths of over 36,000 people, cooled the summer temperatures of the northern hemisphere by 0.3°C, and sparked a renewed interest in volcanology.
Here are 10 facts about the deadly eruption.
1. 1883 was not the first time Krakatoa had erupted
Krakatoa had been dormant for over 200 years when it erupted in 1883, but earlier records show that it had been known as the ‘Fire Mountain’ by Javanese people for centuries and some have hypothesised it erupted catastrophically in the 6th century, causing global climate changes as a result.
In 1680, Dutch sailors reported seeing Krakatoa erupting and picking up large pieces of pumice, and evidence of lava flows from this time was found in the 19th century.
2. The volcano erupted over several months, not just days
Krakatoa was a volcanic island in the Sunda Strait, between Java and Sumatra in Indonesia, part of the ‘Ring of Fire’. In May 1883, Krakatoa began erupting ash and steam to a height of 6km, and generating explosions so loud they were heard nearly 100 miles away.
In June, further eruptions generated enough ash to create a thick black cloud which hung over the volcano for several days. Tides started changing and ships reported pumice in the oceans.
The climactic – or main – phase of the eruption began on 25 August and finished by 27 August. Over 36,000 people were killed in that time.
3. We know about the eruption in great detail thanks to Rogier Verbeek
Verbeek was a Dutch geologist living in Java who had conducted research into the geology of the region in previous years. Following the 1883 eruption he travelled the affected regions, compiling eyewitness accounts and personally observing the destruction the volcano had wreaked.
His 550 page report was published by the government of the Dutch East Indies in 1885. The data and studies within also helped spark the beginning of modern volcanology.
4. The volcano generated the loudest sound in recorded history
Krakatoa’s climactic phase generated the loudest sound in recorded history. At 10:02am on 27 August, during its final stages of eruption, explosions shook the volcano and surrounding areas. The sound was heard thousands of miles away in Western Australia and Mauritius, and the sound wave generated travelled the world 7 times over in the following 5 days.
5. Tsunamis were the most deadly force generated by Krakatoa
As the volcano erupted, spewing ash and pumice into the sea in the form of a pyroclastic flow, it triggered tsunamis of up to 40m high and destroyed up to 300 villages along the Sunda Strait. Waves from the tsunamis rocked ships as far away as South Africa.
One of the most miraculous stories of Krakatoa is the survival of the ship Gouverneur Generaal Loudon, which was sailing north to Teluk Betung. Instead of trying to find port when the eruption worsened and the first tsunamis hit, the captain, Johan Lindemann, steered the ship head on into the wave of the tsunami. His decision to do so saved the lives of his passengers and crew, who subsequently rode out the effects of the eruption.
6. But pyroclastic flows weren’t far behind
Pyroclastic flows are dense flows made up of pumice, volcanic ash, hot gas and newly solidified lava. They race down the slopes of a volcano at an average speed of 100km/h. Despite the fact Krakatoa was an island, the flow travelled across the sea on a cloud of super-heated steam, hitting nearby islands and coastline with immense force. It’s thought around 4,000 people were killed by the arrival of the flow, which travelled several kilometres in land.
7. Krakatoa’s eruption affected the whole world
The volcano poured millions of cubic metres of gas and ash into the atmosphere, creating a blanket and making average temperatures lower for the next year. It also led to increased rainfall in some parts of the world, and delivered amazing fiery sunsets across the world.
Some have even hypothesised that the orange background of Edvard Munch’s famous painting, The Scream, was inspired by the post-Krakatoa skies that were seen around the world at that point in time.
Bodies washed up on the shores on Indonesia, India and Africa for months after the August eruption.
8. The island of Krakatoa was almost completely destroyed
The volcano’s immensely powerful eruption destroyed almost all of the island of Krakatoa and several of the islands in the surrounding archipelago. The Krakatoa volcano itself collapsed into a caldera, a hollow that forms once a magma chamber is empty.
Anak Krakatoa, a new island, emerged from the caldera in 1927 and has been growing steadily ever since. An underwater collapse generated a deadly tsunami in 2018, and it remains of interest to volcanologists as a relatively new volcano.
9. Part of the disaster zone is now a national park
Much of the western part of Java was devastated by the effects of Krakatoa: flattened by the tsunami, covered in ash and a large proportion of the population dead. As such, much of the surrounding lowland was effectively rewilded, with flora and fauna flourishing in the area.
The Ujung Kulon Nature Reserve was officially created in 1957 and today encompasses 1,206 km2.
10. It probably won’t be the last eruption
Many volcanologists are concerned that Krakatoa is far from dormant. Whilst the old volcano no longer exists, Anak Krakatoa remains a potential threat. The proximity of houses and villages to the coastline, combined with an inefficient tsunami warning system means many communities are extremely vulnerable should any further eruptions take place.