Major Quakes Shake Sumatra
April 11, 2012
Indonesia’s Aceh province was shaken this morning by two major earthquakes–one with a magnitude of 8.6, the other measuring 8.3. The earthquakes were centered below the Indian Ocean at a depth of 20 miles (33 kilometers), some 300 miles (495 kilometers) off the coast of Banda Aceh, the provincial capital. Fearing a tsunami like the disastrous one in 2004, the Pacific Tsunami Warning Center issued a tsunami warning. The warning was cancelled after no massive waves developed from the quake. The Indian Ocean tsunami of 2004 killed some 250,000 people in coastal areas of Southeast Asia, South Asia, and East Africa.
An earthquake under the ocean may cause a tsunami, a series of ocean waves that can cause tremendous destruction along coastlines. (World Book illustration by Matt Carrington)
Indonesia is regularly struck by earthquakes. The country’s island of Sumatra is close to an active subduction zone, where the Indian-Australian tectonic plate presses into and under the Eurasian plate. The collision of the plates has created a huge depression on the ocean floor known as the Sunda Trench. Strain between the plates at this depression is eventually released in the form of an earthquake.
Additional World Book articles
- Big Waves: Tracking Deadly Tsunamis (a special report)
- When the Earth Moves (a special report)
- Indonesia 2004 (Back in Time article)
- Indonesia 2005 (Back in Time article)
