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Krakatoa Facts

Krakatoa is located in the Pacific Ring of Fire. It’s an active volcano with a history of eruptive activity.

Krakatoa, an Indonesian volcano, erupted in August 1883. It was one of the deadliest volcanic eruptions in modern history, killing 36,000 people. This eruption emitted 11 cubic miles of ash.

The Island

It lies along the Indian-Australian and Eurasian plates, a zone of high volcanic and seismic activity. Volcanic activity occurs due to the subduction of the Indo-Australian tectonic plate.

The island is 5.5 miles long and 3 miles wide (5 by 9 kilometers).

Rakata was the largest and most active of the three peaks that existed before 1883.

There is evidence that a previous large eruption left an undersea caldera between Krakatoa and the two nearby islands, Lang and Verlatan.

Active Volcano

Krakatoa is an active volcano, so it will erupt one day. It displayed its power as early as the 1600s. A catastrophe loomed 200 years later.

A German warship reported seeing ash clouds over Krakatoa in May 1883. He estimated the cloud to be about 9 miles (12 km) high.

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During the next two months, commercial and charter boats visited the area to see the constantly erupting volcanic clouds, unaware of any danger.

The Eruption

One of these cones erupted on May 20, 1883, with ash clouds reaching heights of 6 miles (10 km).

By May, the activity had slowed. It began again on June 19 and ended on August 26.

At 12:53 pm, the initial blast sent a cloud of gas and debris 15 miles (24 km) above Perboewatan.

This caused a magma chamber rupture allowing seawater to contact hot lava. A phreatomagmatic event occurs.

The eruption had a VI of 6 and had the explosive power of 200 megatons of TNT.

Over 300,000 square miles (800,000 square km) of ash fell over an area nearly five cubic miles (21 cubic km) in size upon the eruption of Krakatoa.

Massive explosions were heard at 10:00 AM on August 27 in Australia, and ash was sent 50 miles (80 kilometers) into the sky.

Only a small islet remained after the eruption. Ashes and pumice fragments covered Verlaten and Lang islands and Rakata’s remaining southern portion.

What Happened After the Explosion

After the explosions, the volcano collapsed into the sea, creating a 120-foot-high wall of water. It engulfed nearby islands.

In the region and around the world, pyroclastic flows, volcanic ash, and tsunamis combined for devastating effects.

The waves wiped out 165 coastal villages. On Sumatra, the steamship Berouw was carried nearly a mile inland, killing all its crew.

Captain Lindemann of the Loudon ship turned his bow to face the wave to help ride the crest of the wave. But the island it anchored on was leveled.

After the explosions, a 120-foot (37-meter) wave hit nearby Java and Sumatra coastal towns, killing 36,000 people.

It took three days for the light to return. Ash fell 3,775 miles away (6,076 km), landing on ships.

For five years, plant and animal life on the Krakatoa island group was buried under a thick layer of sterile ash.

After 13 days, a layer of sulfur dioxide and other gases began to filter sunlight through the ash. This caused weird sunsets in Europe and North America.

Anak Krakatoa – Child of Krakatoa,

44 years later, Javanese fishermen spotted a plume of steam and debris erupting from the collapsed caldera.

A new cone’s rim rose above sea level in weeks. Anak Krakatoa, or Child of Krakatoa, grew into a small island after a year.

Anak Krakatoa has grown 6.8 m per year since the 1950s.

It has been active since then. Alarms went off in 1994, 2008, 2009, 2014, and recently around July 2018. Anak Krakatoa is still active, so Indonesians are on high alert.