Krakatoa, or Krakatau (Indonesian: Krakatau), is a volcanic island situated in the Sunda Strait between the islands of Java and Sumatra in the Indonesian province of Lampung. The name is also used for the surrounding island group comprising the remnants of a much larger island of three volcanic peaks which was obliterated in a cataclysmic 1883 eruption, unleashing huge tsunamis (killing more than 36,000 people) and destroying over two-thirds of the island.

 

The eruption of Krakatoa in August 1883 was one of the most deadly volcanic eruptions in modern history. It is estimated that more than 36,000 people died. Many died as a result of thermal injury from the blasts and many more were victims of the tsunamis that followed the collapse of the volcano into the caldera below sea level. The beginning of the amazing events at Krakatoa in 1883 date to May 20 when there were initial rumblings and venting from the volcano, which had been dormant for about 200 years. Over the next three months, there were regular small blasts from Krakatoa out of three vents.

In May 1883, the captain of the Elizabeth, a German warship, reported seeing clouds of ash above Krakatau. He estimated them to be more than 6 miles (9.6 km) high. For the next two months, commercial vessels and chartered sightseeing boats frequented the strait and reported thundering noises and incandescent clouds. On August 11, ash started spewing from the small mountain. Eruptions got progressively stronger until August 26, when the catastrophe began.

At noon, the volcano sent an ash cloud 20 miles into the air and tremors triggered several tsunamis. This turned out to be just a small indication, however, of what would follow the next day. At 12:53 p.m. on Sunday the 26th, the initial blast of the eruption sent a cloud of gas and debris an estimated 15 miles (24 km) into the air above Perboewatan. It is thought that debris from the earlier eruptive activity must have plugged the neck of the cone, allowing pressure to build in the magma chamber.

On the morning of the 27th, four tremendous explosions heard as far away as Perth, Australia, some 2,800 miles (4,500 km) distant, plunged both Perboewatan and Danan into the caldera below the sea. For four-and-a-half hours beginning at 5:30 a.m. on August 27, there were four major and incredibly powerful eruptions. The last of these made the loudest sound ever recorded on the planet. It could be heard as far away as central Australia and the island of Rodrigues, 3,000 miles from Krakatoa. The airwaves created by the eruption were detected at points all over the earth.

The explosions hurled an estimated 11 cubic miles (45 cubic km) of debris into the atmosphere darkening skies up to 275 miles (442 km) from the volcano. In the immediate vicinity, the dawn did not return for three days. Barographs around the globe documented that the shock waves in the atmosphere circled the planet at least seven times. Within 13 days, a layer of sulfur dioxide and other gases began to filter the amount of sunlight able to reach Earth.

The atmospheric effects made for spectacular sunsets all over Europe and the United States. Average global temperatures were up to 1.2 degrees cooler for the next five years. Each eruption of Krakatoa caused massive tsunamis. When the volcano collapsed into the ocean, it generated a tsunami at least 120 feet tall, which was so powerful it tossed blocks of coral weighing 600 tons onshore, carried a steamship one mile inland, killing all 28 crewmen, and wiped out 165 villages in nearby Java and Sumatra.

The volcano threw so much rock, ash and pumice into the atmosphere that, in the immediate area, the sun was virtually blocked out for a couple of days. Within a couple of weeks, the sun appeared in strange colours to people all over the world because of all the fine dust in the stratosphere. Over the ensuing three months, the debris high in the sky produced vivid red sunsets. In one case, fire engines in Poughkeepsie, New York, were dispatched when people watching a sunset were sure that they were seeing a fire in the distance.

Further, there is speculation that Edvard Munch’s 1893 painting “The Scream” depicting a psychedelic sunset may have actually been a faithful rendering of what Munch saw in Norway in the years following the eruption of Krakatoa. The amount of dust in the atmosphere also filtered enough sun and heat that global temperatures fell significantly for a couple of years. Krakatoa has left only a tiny fraction of its former self. However, in the intervening years, a small island, Anak Krakatoa (“Son of Krakatoa”) has arisen from the sea. It is growing at an average of five inches every week. This island is receiving a great deal of scientific attention, as it represents a chance to see how island ecosystems are established from scratch.

References:

1. https://en.wikipedia.org
2. http://www.history.com
3. http://mentalfloss.com