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Staggering Facts That Show Why Krakatoa Was A Monster Volcanic Eruption

1800s | July 20, 2019

1883-Island and volcano of Krakatoa, Straight of Sunda, (before eruption). Engraving. (Getty Images)

Mother Nature often shows us her power and strength, and in August 1883, she was feeling particularly boastful. The eruption of Krakatoa in Indonesia was one of the worst natural disasters of the century, but it helped scientists better understand the nature of volcanoes. Here are some astonishing facts to show why Krakatoa was so devastating. 

The volcano showed signs of eruption for months. (legacy.earlham.edu)

There Was Plenty of Warning

Months before the massive eruption, Krakatoa showed signs that the volcano was getting cranky. Locals reported seeing smoke from the mountain, located between the islands of Java and Sumatra in the Sunda Strait. The captain of a German ship, The Elizabeth, noted clouds of ash forming above the volcano when he passed by in May 1883. In his log, he wrote that the ash cloud was more than 6 miles high. In addition to this report, other commercial ships reported seeing glowing clouds above the mountain and reported hearing loud, low rumblings coming from the volcano. 

The volcanic activity attracted the attention of people living on islands near Krakatoa. (scmp.com)

A Two-Day Eruption

The eruption of Krakatoa began just after noon on Sunday, August 26, 1883, when an explosion sent a huge cloud of super-heated gas and debris more than 15 miles into the air. Present-day volcanologists think that this blast blocked off the cone of the volcano and caused pressure to build up. The next morning, on August 27, Krakatoa was rocked by four tremendous explosions. The noise was so incredibly loud—one of the loudest noises in human history—that it was heard more than 2,800 miles away in Perth, Australia. 

The blast from Krakatoa's eruption was one of the loudest sounds ever. (history.com)

A Powerful Blast

The explosion of Krakatoa had the explosive force of about 200 megatons of TNT. The devastating bomb dropped on Hiroshima, by comparison, had an explosive force of about 20 megatons. On the Volcanic Explosion Index, it rated as a 6. It's not a very wide scale. The blast sent a wave of atmospheric pressure around the world that was recorded by every barograph recorder in the world at that time. These barographs showed that the pressure wave circled the earth 7 times in the days following the blast until the energy finally dissipated. 

The pyroclastic flow killed many people. (indovolcano.blogspot.com)

Ocean Water Met Lava

Krakatoa’s huge magma chamber collapsed, and ocean water pored into the caldera and produced what volcanologists call a phreatomagmatic event. This occurred when the water instantly turned to steam that rolled horizontally from the blast at speeds of more than 60 miles per hours. The pyroclastic flow was extremely hot and contained toxic gasses. 

When the caldera collapsed, a massive tsunami formed. (volcanodiscovery.com)

A Staggering Death Toll

In all, the eruption of Krakatoa killed an estimated 36,417 people. On the island of Sumatra, more than 1,000 people perished. On the nearby island of Sebesi, not a single person survived. When the caldera collapsed into the sea, a tsunami formed and raced across the Sunda Straits. The majority of the casualties came from the pyroclastic flows and tsunami that totally destroyed more than 165 villages on the islands and coasts. 

The tsunami from Krakatoa spread around the globe. (suhaneye.blogspot.com)

Islands of Pumice

The blast at Krakatoa wiped out more than two-thirds of the volcano, leaving just a smoldering stump in its wake. North of Krakatoa, new islands were formed from the piles of ash and smoking pumice that filled the 118-foot deep sea. Floating rafts of pumice—many bearing the skeletal remains of volcano victims—were reported to have washed ashore in eastern Africa in the year following the eruption of Krakatoa, which must have left a lot of confused locals with conspiracy theories about rock pirates.

The enormous tsunami killed thousands of people. (thesun.co.uk)

Worldwide Impact

When Krakatoa erupted, it sent more than 11 cubic miles of dust and debris into the atmosphere, blotting out the sun for more than three days. Nearly 4,000 miles away, ash fell on sailing ships. For more than two weeks, the sunlight was unable to fully reach to Earth. It created a lot of pretty sunsets but also caused global temperatures to drop. The eruption of Krakatoa was one of the most momentous volcanic eruptions in the modern era, whether it was remembered for destroying entire islands or its mood lighting.

Tags: deadliest volcanoes, history

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Karen Harris

Writer

Karen left the world of academic, quitting her job as a college professor to write full-time. She spends her days with her firefighter husband and four daughters on a hobby farm with an assortment of animals, including a goat named Atticus, a turkey named Gravy, and a chicken named Chickaletta.