The eruption of Krakatoa Island in August 1883 was THE most deadly volcanic explosion in modern history. More than 36,000 people in over 300 coastal villages perished in the most ghastly ways imaginable. Many died of burns and suffocation from the super-heated pyroclastic blasts that blew the peak off the island. Thousands more drowned from the 4 Tsunamis that followed when the volcano collapsed into the sea.
The Indonesian island of Krakatau (Krakatoa) sits in the narrow Sunda Straits between Sumatra to the north and Java to the south. Before the 1883 eruption, the uninhabited tropical island had no less than 3 volcanic peaks. They were Perboewatan, the most active, Danan, in the middle, and Rakata, the tallest. Krakatau and its two nearby islands were remnants of a previous eruption that left an undersea caldera simmering beneath the sea floor.
The eruption story starts 3 months before. Early in the morning of 20 May 1883, an 11 kilometer high cloud of ash and pumice plumed above the normally silent Krakatau, the first eruption in over two centuries. Over the next 2 months, it would deliver similar spectacles, all of which brought churning clouds of incandescent ash high into the warm tropical skies. People living in the nearby Dutch colonies on Java & Sumatra actually held parties celebrating nature’s spectacular fireworks. These awe-inspiring displays, however, were a prelude of far worse things to come.
Celebrations would come to a tragic halt in late August 1883.
At 12:53 o’clock PM on Sunday 26 August, the eruption’s first major blast sent a cloud of hot gas, ash and pumice 24 km into the afternoon sky! Debris from the smaller summer eruptions had plugged the neck of the cone, allowing pressure to build in the magma chamber. This surprise initial blast generated an eardrum-rupturing barrage accompanied by a black churning cloud that quickly turned daytime into night. Terrified villagers and Dutch colonists covered their mouths and fled into houses and huts to escape the raining storm of hot ash and pumice. This was but the opening salvo to a climactic eruption the next day.
Colonists and villagers slept anxiously through the night, praying the worst was over. Then the first of 4 stupendous eruptions began at 5:30 AM Monday morning, awakening all. They once again faced skies choked with pumice and hot ash. It all climaxed in a colossal blast at 10:00 AM that literally blew Krakatau Island apart. People heard the noise over 4600 km away, throughout the Indian Ocean – from Sri Lanka in the west, to Australia in the east. TWO-THIRDS of the island collapsed beneath the sea, into the now vacated magma chamber. Twenty-three square kilometers of the island, including all of Perboewatan and Danan, fell into a caldera 6 kilometers across.
The explosive force was estimated at 200 megatons of TNT. By comparison, the 1945 atomic bomb that devastated Hiroshima was a mere 20 kilotons. When the northern half of the island dropped beneath the ocean, it generating a series of devastating pyroclastic ash flows at sea level. Black clouds blasted across the waters of the Sundra Straits at speeds up 100 kph. Dazed villagers had barely enough time to take in the destruction of Krakatoa island before it hit. Blistering pyroclastic flows struck southern Sumatra and western Java with a vengeance. It was so hot that it incinerated entire villages and their occupants.
One thousand people alone died in the Sumatra town of Ketimbang, over 40 kilometers away. Dutch Controller Willem Beijerinck lived and worked in Ketimbang with his wife Johanna and their three children. Huddled in their house, he seriously contemplated killing his wife and children to spare them the hideous death of suffocation by hot ash. The family managed to survive by heading to high ground soon after the Sunday eruption.
Still Krakatau was not finished, as the worst was yet to come.
The collapse of the island into the sea generated immense tsunamis that ravaged the coastlines on both sides of the strait. Thousands of people who survived burns from the hot ash were now faced with a Tidal Wave 120 feet tall. Completely unprepared, survivors scrambled frantically for higher ground. Most of the closest islands, after first being overwhelmed by the hot ash, were totally submerged by the fierce wave. It stripped away of all vegetation, washing helpless people away, and removing all signs of human occupation.
The tsunami carried the helpless steamship Berouw a mile inland on Sumatra and beached in a river bed; all 28 crew members died. The Loudon was anchored in Lampong Bay, near the village of Telok Betong when the first wave approached. The ship’s Captain Johan Lindemann quickly raised anchor and turned its bow to face the tsunami. The ship somehow managed to ride over the steep crest. The wave continued past them and the shocked crew watched as the waters consumed the town until nothing remained but the open sea.
All told, the explosions hurled 45 cubic kilometers of debris into the atmosphere darkening skies 440 km away. Survivors did not see sun over Sumatra and Java for three days. Geologists recorded the shock wave around the globe as far away as London, and circled the planet seven times. Within 13 days, a layer of volcanic gas had circled the Earth, making for spectacular sunsets over Europe and the Americas. Average GLOBAL temperatures were up to 1.2 degrees C COOLER for the next FIVE years! Mother Nature had indeed put on one of her better shows.
Nobody knows how many native souls were washed out to sea by the tsunamis.
For months, the Sunda Straits were clogged with so much debris that it looked like solid ground, peppered with decaying corpses. Relief ships were unable to reach devastated coastal communities like Telok Betong for weeks. The official number of dead, calculated by the Dutch East India Company was 36,417, ninety percent of which were directly killed by the ash or tsunamis. Truer estimates including native populations and the aftermath are over 100,000 dead. Krakatoa then went to sleep.
In December 1927, local fishermen in the Sundra Strait were shocked when a column of steam began spewing from the old collapsed caldera. Krakatau had awakened after 44 years of silent slumber. Within weeks, a small, new island cone appeared above sea level. Within a year, it grew into a small island, named appropriately Anak Krakatau, Child of Krakatau.
The new peak continues to grow on average 7-9 meters every year. Krakatoa Jr. was now a 1,109 ft. island mountain again and up to its old tricks. It erupted on December 22, 2019 spewing ash and lava into the air. The eruption caused a 5 meter deadly tsunami in Banten, Pampung and Anyer. 426 people lost their lives. Anak Krakatau has erupted since in 2019, 2023, and as recently as September 11, 2026, disrupting regional air travel. Let us hope these minor eruptions are the worst it has to offer the tranquil South Pacific.
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