Disaster Strikes - Krakatoa Volcano 1883 Deadly Eruption (Indonesia)
- 6 years ago
The eruption of Krakatoa, or Krakatau, in August 1883 was one of the most deadly volcanic eruptions of 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 eruption also affected the climate and caused temperatures to drop all over the world.
The island of Krakatau is in the Sunda Strait between Java and Sumatra. It is part of the Indonesian Island Arc. Volcanic activity is due to subduction of the Indo-Australian tectonic plate as it moves northward toward mainland Asia. The island is about 3 miles wide and 5.5 miles long (9 by 5 kilometers). Before the historic eruption, it had three linked volcanic peaks: Perboewatan, the northernmost and most active; Danan in the middle; and the largest, Rakata, forming the southern end of the island. Krakatau and the two nearby islands, Lang and Verlatan, are remnants of a previous large eruption that left an undersea caldera between them.
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. People on nearby islands held festivals celebrating the natural fireworks that lit the night sky. Celebration would come to a tragic halt on Aug. 27.
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.
The initial explosion ruptured the magma chamber and allowed seawater to contact the hot lava. The result is known as a phreatomagmatic event. The water flash-boiled, creating a cushion of superheated steam that carried the pyroclastic flows up to 25 miles (40 km) at speeds in excess of 62 mph (100 kph). The eruption has been assigned a rating of 6 on the Volcanic Explosion Index and is estimated to have had the explosive force of 200 megatons of TNT. (For purposes of comparison, the bomb that devastated Hiroshima had a force of 20 kilotons, nearly ten thousand times less explosive as the Krakatoa eruption. The Krakatoa eruption was about ten times more explosive than the Mount St. Helens explosion of 1980 with a VEI of 5.)
Tephra (volcanic rock fragments) and hot volcanic gases overcame many of the victims in western Java and Sumatra, but thousands more were killed by the devastating tsunami. The wall of water, nearly 1
The island of Krakatau is in the Sunda Strait between Java and Sumatra. It is part of the Indonesian Island Arc. Volcanic activity is due to subduction of the Indo-Australian tectonic plate as it moves northward toward mainland Asia. The island is about 3 miles wide and 5.5 miles long (9 by 5 kilometers). Before the historic eruption, it had three linked volcanic peaks: Perboewatan, the northernmost and most active; Danan in the middle; and the largest, Rakata, forming the southern end of the island. Krakatau and the two nearby islands, Lang and Verlatan, are remnants of a previous large eruption that left an undersea caldera between them.
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. People on nearby islands held festivals celebrating the natural fireworks that lit the night sky. Celebration would come to a tragic halt on Aug. 27.
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.
The initial explosion ruptured the magma chamber and allowed seawater to contact the hot lava. The result is known as a phreatomagmatic event. The water flash-boiled, creating a cushion of superheated steam that carried the pyroclastic flows up to 25 miles (40 km) at speeds in excess of 62 mph (100 kph). The eruption has been assigned a rating of 6 on the Volcanic Explosion Index and is estimated to have had the explosive force of 200 megatons of TNT. (For purposes of comparison, the bomb that devastated Hiroshima had a force of 20 kilotons, nearly ten thousand times less explosive as the Krakatoa eruption. The Krakatoa eruption was about ten times more explosive than the Mount St. Helens explosion of 1980 with a VEI of 5.)
Tephra (volcanic rock fragments) and hot volcanic gases overcame many of the victims in western Java and Sumatra, but thousands more were killed by the devastating tsunami. The wall of water, nearly 1