The 1883 Eruption of Krakatoa

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Podcast Transcript

On the morning of August 27, 1883, one of the most destructive natural disasters of the 19th century occurred between the islands of Java and Sumatra, in what is today the nation of Indonesia. 

After weeks of low-level rumblings, a volcanic eruption totally obliterated the mountain that it had formed. 

The devastation wasn’t limited to the immediate area around the volcano. The blast’s effects literally affected the entire planet.

Learn more about the 1883 eruption of Krakatoa and its devastating impact on this episode of Everything Everywhere Daily.

Volcanoes are arguably the most devastating natural event on the planet.  Hurricanes and earthquakes certainly can do a lot of damage, but for the most part their effects, as bad as they can be, are mostly localized. 

A volcano has the ability to effect the entire planet. If you remember back to my episode on the Mount Tambora Eruption of 1815, it spewed enough particulate matter into the atmosphere that it was called the year without a summer. Global temperatures dropped so much that crops failed around the world. 

The Tambora Eruption was was the largest volcanic eruption in the last 10,000 years. Yet as massive as the eruption was, given communications at the time most people didn’t know about it outside of what is today Indonesia. 

There was no rapid communication at that point in the 19th century 

The eruption of Krakatoa, on the other hand, was known around the world soon after it happened. 

The story of the eruption of Krakatoa begins in the Sunda Strait, the water way between the islands of Java and Sumatra, the two largest islands in Indonesia.

Krakatoa was located on an island on the strait. In the local Bahasa language, the island is known as Krakatau. 

Krakatau, along with the rest of Indonesia, is located in what is known as the Ring of Fire. If you remember several of my previous episodes, the Ring of Fire is a ring that loops around most of the Pacific Ocean, and it has the world’s largest collection of volcanoes. 

All of the vulcanism and earthquakes are due to tectonic activity. Along with much of Indonesia, the primary mechanism that was responsible for the creation of Krakatoa was the Australian plate subducting under the Eurasian plate, 

When you have a subduction zone, the subducting plate will melt below the surface under extreme pressures and temperatures, and when the melt percolates up up, you get volcanoes. That is a very short version of how subduction zones cause volcanoes in general. 

Because of its location and these conditions, Indonesia has 130 active volcanoes, the most of any country in the world. 

Krakatoa had been active for centuries before the 1883 eruption. There might have been an eruption in 416, but the only evidence is second-hand documentation and no real geologic evidence. 

There were seven recorded eruptions between the 9th and 16th centuries, and another well-documented eruption took place in 1680.

In the years before the 1883 eruption, there was increased activity on Krakatoa. There were minor earthquakes and steam started to vent. However, it was nothing that would have indicated that something major was about to happen. 

Krakatoa had three peaks at the time: Rakata, 820 meters tall, was to the south; Danan, 450 meters tall, was in the middle; and Perboewatan, 120 meters tall, was to the north.

Things began to change on May 20, 1883. The steam emissions increased, and ash began being expelled. The ash plumes that came out of the northernmost Perboewatan peak were significant. The ash was reaching a height of 6 kilometers or 20,000 feet, and explosions were heard over 160 kilometers away in Jakarta. 

By early August, the activity had increased to a point where the island couldn’t be seen by ship, and when a research team landed on the island to investigate, they found all the vegetation dead, with half a meter of ash covering the island. 

By August 25, explosions were occurring approximately every ten minutes. Ash columns were now rising as high as 27 kilometers into the sky.

The day for which Krakatoa is remembered, and the reason I’m even doing a podcast episode on it, took place on August 27, 1883. 

Three explosions took place. The first erupted at 5:30 am local time, the second took place at 6:40 am, and the third, final, and by far the greatest explosion took place at 10:02 am. 

This explosion was a monster. It was arguably the greatest explosion recorded in human history. It was heard in Perth, Australia, 3,110 kilometers or 1,930 miles away, and on the island of Rodrigues in the Indian Ocean, 4,800 kilometers or 3,000 miles away.

Sailors on the RMS Norham Castle, which was off the coast of the island of Sumatra at the time, had their eardrums burst from the sound. A gas pressure gauge was broken in Jakarta, then known as Batavia, 100 miles away.

It was estimated to have had a loudness of 180 dB, and the thing to remember with decibels is that it is a logarithmic scale. 140 dB is the point where the sound can cause injury. 

The pressure wave from the blast literally went around the world. It traveled from Krakatoa to its antipodal point on the other side of the Earth. Over the course of five days, the pressure wave was measured seven times, going around the world and then back again. 

The explosion sent 25 cubic kilometers or six cubic miles of rock and ash into the atmosphere, creating a massive ash cloud that darkened the skies and reduced temperatures worldwide.

In that moment, the island ceased to exist. All three of the peaks on the island were vaporized and sent into the atmosphere. 

Here, I should note the differences between the Tambora eruption of 1815 and the Krakatoa eruption of 1883. The Tambora eruption was a larger eruption in terms of the total volume of ejecta discharged from the volcano. However, the eruption took place over several days. 

The Krakatoa eruption was mostly one massive explosion, larger than any other we know of. 

The explosion was only the beginning of the problems. 

A later pyroclastic surge from the mountain crossed the strait and fell upon the town of Ketimbang. Everyone in the community was killed. 

The small island of Sebesi, nearby, had a population of 3000 people. The explosion completely wiped it out. 

There were parts of the island of Sumatra that were hit with pyroclastic flows that were 40 kilometers or 25 miles away. 

If you remember from my episode on Pompeii, a pyroclastic flow is one of the most terrifying things in nature. It is an incredibly fast-moving cloud of super-heated ash that you can’t outrun. 

The pyroclastic flows off Krakatoa went over the water, creating a mist of superheated steam that covered the sea. 

However, the explosion itself was not the most devastating aspect of the eruption. The thing that killed the most people was the tsunami it created. 

The tsunami destroyed many communities along the coast. The city of Merak on the island of Java was hit by a tsunami that was 46 meters or 150 feet high.

A steamship named Berouw was deposited nearly a mile inland on Sumatra, killing all its crew members.

Ships as far away as South Africa reported encountering the tsunami. Even tidal gauges in the English Channel measured a rise in sea levels from the tsunami, which meant that the wave had to go around Africa and up the Atlantic Ocean to get there. 

While the major eruptions were over on August 27, there was continued activity for several months, but nothing close to what happened on the 27th.

Unlike the Tambora eruption, the entire world quickly knew what had happened. Telegraph cables spread the word of the event quickly, allowing scientists to better track the eruption’s results. It was one of the first global news events where people were able to follow what was happening across the globe in almost real-time. 

News of the eruption went via telegraph cable from Batavia to Singapore and from Singapore to the rest of the world. London was aware of the eruption just a few hours after it happened. In comparison, when Abraham Lincoln was shot less than 20 years earlier, news of the event took two weeks to reach Europe. 

In comparison, the New York Times managed to publish a story on August 28th. The New York Times reported:

“Terrific detonations were heard yesterday evening from the volcanic island of Krakatoa. They were audible at Soerkrata, on the island of Java. The ashes from the volcano fell as far as Cheribon, and the flashes proceeding from it were visible in Batavia.”

After the dust had literally settled, the Dutch, who controlled Indonesia at the time, conducted an investigation into the impact of what actually happened. 

They found that 70% of the island where Krakatoa had existed was now gone. Most of it either went into the atmosphere or wound up on the sea floor. 

The official death toll from the eruption was put at 36,417 people. However, many consider this number to be a very low estimate. For years afterward, remains of humans were discovered, sometimes floating on rafts of pumice in the ocean. Some estimates put the death toll as high as 120,000.

The end of the eruptions, the tsunami, and the pyroclastic flows was not the end of the story. 

All of the dust ejected into the sky remained suspended in the atmosphere for quite some time. It ushered in what is known as a volcanic winter. 

In the year following the eruption, temperatures during the summer in North America dropped 0.4 °C or 0.72 °F. In addition to a decrease in temperatures, the world also saw an extended period of dramatic red and orange sunrises and sunsets. 

The particles in the atmosphere allowed scientists to identify for the first time a phenomenon they dubbed the Jet Stream. 

The famous 1893 painting, The Scream, by Edvard Munch shows an orange sky in the background. It is believed to depict the type of sunsets that were seen in Norway during this period. 

Even the climatic changes weren’t the end of the Krakatoa story. 

With almost the entire island having been totally obliterated, researchers had an excellent opportunity to witness how life can spread on an island totally devoid of it. 

The first team to set foot on the island after the eruption in May 1884 found nothing but a spider 

Almost six months later, the first sprouts of grass began appearing on the island. 

Under the sea, a new lava dome had been forming. In 1927, for the first time, Anak Krakatoa peaked past the water line, forming a new island.  Anak Krakatoa has been erupting regularly since 2020, with the most recent eruption as of the time of this recording in September 2023. 

In 1921, the crater that was left of Krakatoa was named a nature reserve, and in 1991, the “Ujung Kulon National Park and Krakatau Nature Reserve” was named a UNESCO World Heritage site. 

The eruption of Krakatoa in 1883 was one of the biggest natural disasters in the past 200 years, and the biggest explosion and sound in recorded human history.

It was also one of the first global news stories to be reported in real-time via the telegraph. 

With the rise of Anak Krakatoa, it is not out of the question to say that future generations might experience someone similar again.