One of the most powerful volcanic eruptions in recorded history occurs on Krakatoa (also called Krakatau), a small, uninhabited volcanic island east of Sumatra and west of Java, on August 27, 1883. Heard 3,000 miles away, the explosions threw five cubic miles of earth 50 miles into the air, created 120-foot tsunamis and killed 36,000 people.
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Krakatoa exhibited its first stirrings in more than 200 years on May 20, 1883. A German warship passing by reported a seven-mile high cloud of ash and dust over Krakatoa. For the next two months, similar explosions would be witnessed by commercial liners and natives on nearby Java and Sumatra. With little to no idea of the impending catastrophe, the local inhabitants greeted the volcanic activity with festive excitement.
On August 26 and August 27, excitement turned to horror as Krakatoa literally blew itself apart, setting off a chain of natural disasters that would be felt around the world for years to come. An enormous blast on the afternoon of August 26 destroyed the northern two-thirds of the island; as it plunged into the Sunda Strait, between the Java Sea and Indian Ocean, the gushing mountain generated a series of pyroclastic flows (fast-moving fluid bodies of molten gas, ash and rock) and monstrous tsunamis that swept over nearby coastlines. Four more eruptions beginning at 5:30 a.m. the following day proved cataclysmic. The explosions could be heard as far as 3,000 miles away, and ash was propelled to a height of 50 miles. Fine dust from the explosion drifted around the earth, causing spectacular sunsets and forming an atmospheric veil that lowered temperatures worldwide by several degrees.
Of the estimated 36,000 deaths resulting from the eruption, at least 31,000 were caused by the tsunamis created when much of the island fell into the water. The greatest of these waves measured 120 feet high, and washed over nearby islands, stripping away vegetation and carrying people out to sea. Another 4,500 people were scorched to death from the pyroclastic flows that rolled over the sea, stretching as far as 40 miles, according to some sources.
In addition to Krakatoa, which is still active, Indonesia has another 130 active volcanoes, the most of any country in the world.