Home Film Resources Shop
Choose a Force


Forces of Nature

Krakatau, IndonesiaReturn
Anak Krakatau or 'child of Krakatau,' has been built from eruptions since 1927.
Launch Image Gallery

Type: Composite volcano with caldera

The 1883 explosion on an uninhabited island in Indonesia was one of the most catastrophic in history. Before the eruption, this island in the Sunda Straits between Java and Sumatra islands was made up of three stratovolcanoes that had grown together.

In the summer of 1883, one of Krakatau's three cones became active. Sailors reported seeing clouds of ash rising from the island. The eruptions reached a peak in August, culminating in a series of tremendous explosions. The most ear-shattering eruption was heard in Australia, more than 2,000 miles (3,200 kilometers) away.

Ash was sent 50 miles (80 kilometers) into the sky and blanketed an area of 300,000 square miles (800,000 square kilometers), plunging the area into darkness for two and a half days. The ash drifted around the globe, causing spectacular sunsets and halo effects around the moon and sun.

The explosions also sent as much as 5 cubic miles (21 cubic kilometers) of rock fragments into the air. The northern two-thirds of the island collapsed under the sea into the newly vacated magma chamber. Much of the remaining island sank into a caldera about 3.8 miles (6 kilometers) across.

The collapse set off an immense series of tsunamis, or giant sea waves, that traveled as far as Hawaii and South America. The largest wave loomed 120 feet (37 meters) high and destroyed 165 nearby settlements. All vegetation was stripped bare, structures were demolished, and some 30,000 people were washed out to sea in Java and Sumatra.

Krakatau was quiet until the 1920s, when volcanic activity began again. Since then, eruptions have built a new cone, Anak Krakatau, or "child of Krakatau" in the center of the caldera created in 1883.

AmicaNational Science FoundationNational GeographicGirl Scouts: Where Girls Grow Strong