The Eruption of Krakatoa, 1883

The island of Krakatoa in 1883, prior to the eruption. Getty Images

On August 26, 1883, the triple-peaked volcanic island of Krakatoa rumbled to life in one of the most violent eruptions on record.  The volcano, also known as Krakatau, blew itself apart so explosively over the next two days that people heard the sound as far away as Perth, Australia, 3,110 kilometers (1,930 miles) to the south.  This is believed to be the loudest noise in recorded history.

The volcano sat in the Sunda Strait of what was then the Dutch East Indies, now Indonesia.

  It had been undergoing a series of increasingly powerful eruptions since June of 1883, but around 1:00 in the afternoon on August 26, it entered what geologists call the "paroxysmal phase" of extremely violent eruption.  The ash cloud rose an estimated 27 kilometers into the sky, or 17 miles.  The first and smallest of a series of tsunamis hit the beaches of Java and Sumatra; it did little damage, but the 30 meter waves (98 feet) that struck the next day killed thousands of people around the East Indies. 

August 27 witnessed four major eruption events on Krakatoa, at 5:30 am, 6:44 am, 10:02 am, and 10:41 am local time.  Each of them unleashed major tsunamis; a wave 46 meters (151 feet) high destroyed the city of Merak.  The 10:02 am explosion was so violent that people on the Indian Ocean island of Rodrigues, near Mauritius, 4,800 kilometers (3,000 miles) away heard the sound and thought that they were under attack from a ship's cannon.

  A landslide that ripped away half of the remaining volcanic cone triggered the final cataclysmic eruption at 10:41, utterly destroying the island.

The last eruption sent pyroclasic flows from the volcano that incinerated villages along the Sumatran coast.  A pressure wave reverberated around the world seven times, as shown by barographic readings from across the globe.

  The pressure was so extreme that it blew out the eardrums of sailors in the nearby strait.  Krakatoa sank almost entirely under the sea, with faint mud eruptions over the next two months marking its resting place.

Incredibly, only about 1,000 people were killed directly by Krakatoa.  They were the unfortunate residents of Ketimbang, who died on August 27 when a lateral blast of super-heated ash and gas swept across the bay and engulfed their villages.  This phenomenon is known as a pyroclastic surge.

Many tens of thousands more were killed by the tsunamis that swept through repeatedly.  Dutch officials at the time reported an official death toll of 36,417, but they were not in contact with all the populated areas of the archipelago.  Some later estimates have put the death toll as high as 120,000.  Human bodies or skeletons were reported floating out at sea for moths afterward, and some even washed up on the shores of East Africa.  The westernmost tip of Java was completely depopulated, and has remained unpeopled to this day, so in 1980 the Indonesian government designated the area as Ujung Kulon National Park.

It seems that the survivors and their descendants were wise to build their homes further from the wreckage of Krakatoa.

  In 1927, a new volcanic cone began to rise from the site of the catastrophic 1883 eruption.  It is now approximately 300 meters (984 feet) tall, and has two vents that erupt ash plumes and lava from time to time.