In the Sunda Strait between the Indonesian islands of Java and Sumatra, the volcanic island of Krakatoa has been one of the most geologically violent places on Earth for centuries, its name synonymous with catastrophic eruption and the raw, indiscriminate power of the natural world. The series of cataclysmic explosions that culminated on August 26 and 27, 1883, produced sounds heard on the far side of the planet and generated tsunamis that killed tens of thousands of people along coastlines hundreds of kilometers away.
The island sits within a volcanic archipelago in the Indonesian province of Lampung, a region where the Indo-Australian tectonic plate subducts beneath the Eurasian plate, creating a highly active volcanic zone. The earliest surviving written reference to Krakatoa appears in the Old Sundanese text Bujangga Manik, composed in western Java in the late fifteenth century, which describes it as an island mountain in the middle of the sea. Dutch cartographer Lucas Janszoon Waghenaer labeled the island on a map in 1611 as Pulo Carcata, with pulo being the Sundanese word for island. The name's exact origin remains debated, but the leading theory traces it to Sanskrit words for lobster or crab, a connection supported by the fact that the earliest recorded forms of the name closely resemble those Sanskrit roots.
By the middle of the nineteenth century, Krakatoa had been dormant for so long that it was largely covered in tropical vegetation and considered geologically quiet. Beginning in May 1883, however, a series of preliminary eruptions signaled that something profound was stirring beneath the island. Steam vented from multiple craters, and minor explosions sent ash columns drifting across the strait. These early eruptions attracted scientific observation from Batavia, the capital of the Dutch East Indies, but the scale of what was coming was beyond anyone's expectation.
On the evening of August 26, 1883, the eruptions intensified dramatically. Then, on the morning of August 27, the volcano produced a sequence of explosions of almost inconceivable violence. The largest detonation, which occurred at approximately ten o'clock in the morning local time, has been calculated at a volcanic explosivity index of 6, releasing energy equivalent to roughly 200 megatons of TNT. To place that in perspective, this was approximately 13,000 times the yield of the atomic bomb dropped on Hiroshima and four times the yield of Tsar Bomba, the most powerful nuclear device ever detonated. The explosion was heard 3,600 kilometers away in Alice Springs, Australia, and 4,780 kilometers to the west on the island of Rodrigues near Mauritius, making it arguably the loudest sound ever recorded in modern history. The eruption ejected approximately 25 cubic kilometers of rock and ash into the atmosphere.
The immediate physical destruction was staggering. The explosions destroyed two-thirds of the island of Krakatoa itself, collapsing the volcanic structure into the sea and creating the caldera that defines the site today. The explosions also generated a series of catastrophic tsunamis. Walls of water, some reaching twenty meters in height, swept across coastal settlements on both the Javan and Sumatran shores of the Sunda Strait. According to official records of the Dutch East Indies colonial government, 165 villages and towns near Krakatoa were completely destroyed, and 132 others were seriously damaged. At least 36,417 people died, the vast majority of them from the tsunamis rather than the eruption itself. Many more thousands were injured.
The atmospheric effects of the eruption were felt worldwide. Fine ash and aerosol particles were ejected high into the stratosphere, where they circulated around the globe for years, scattering sunlight and producing vivid red and orange sunsets visible across the world. Average global temperatures dropped noticeably in the year following the eruption. Artists and observers recorded extraordinary atmospheric phenomena, and some researchers have suggested that the fiery skies depicted in Edvard Munch's famous painting The Scream may have been inspired by the eerie atmospheric effects observed over Europe in the months after the Krakatoa eruption.
The caldera left by the 1883 eruption did not remain empty for long on a geological timescale. In 1927, a new volcanic island began emerging from the waters of the caldera, built by ongoing eruptions from below. This island, named Anak Krakatau, meaning Child of Krakatoa, grew steadily in the decades that followed. Periodic eruptions have continued through the twentieth and twenty-first centuries, with notable activity in 2009, 2010, 2011, and 2012. By late 2011, Anak Krakatau had a radius of roughly two kilometers and stood about 324 meters above sea level, growing approximately five meters each year. By 2017, its height had been reported as over 400 meters. Then, in December 2018, a massive collapse of Anak Krakatau's southwestern flank during an eruption generated a deadly tsunami that struck the Sunda Strait coastlines of Java and Sumatra without warning, killing more than 400 people and injuring thousands more. The collapse dramatically reduced the island's height to about 110 meters. New eruptions in the early 2020s continued building a fresh cinder cone from the collapse scar, demonstrating that Krakatoa remains very much an active and dangerous presence in one of the world's most densely populated regions.
