Padang Earthquake (September 30, 2009) and Banda Aceh quake (December 26, 2004) Explained
The great Indo-Australian Plate (Indian Plate) underlies the Indian Ocean and Bay of Bengal and is drifting north-east at an average of 6 cm/year (2 inches per year). The Indo-Australian Plate (Indian Plate) subducts the Burma Plate (Eurasian Plate) at the Sunda Trench. Padang city lies close to this subduction zone. A megathrust fault is the boundary between a subducting and an overriding plate. A megathrust earthquake is produced by a sudden slip along this fault.
The town of Padang has been devastated. At the time of writing 75 people are reported dead with thousands of people trapped under collapsed buildings.
c 1,600 km (994 mi) of faultline slipped (or ruptured) about 15 m (50 ft) along the subduction zone where the India Plate slides (or subducts) under the overriding Burma Plate (Eurasian Plate). The earthquake triggered a series of devastating tsunami along the coasts of most landmasses bordering the Indian Ocean, killing nearly 230,000 people in eleven countries, and inundating coastal communities with waves up to 30 meters (100 feet) high. Coastal locations in Indonesia, Sri Lanka, India, and Thailand suffered most.