The India Plate or Indian Plate is a tectonic plate that was originally a part of the ancient continent of Gondwanaland from which it split off, eventually becoming a major plate. About 50 to 55 million years ago (contested), it fused with the adjacent Australian Plate. It is today part of the major Indo-Australian Plate, and includes the Indian subcontinent and a portion of the basin under the Indian Ocean.
In the late Cretaceous Period about 90 million years ago, subsequent to the splitting off from Gondwanaland of conjoined Madagascar and India, the Indian Plate split from Madagascar. It began moving north, at about 20 cm/yr (8 in/yr),[1] and is believed to have begun colliding with Asia between 50 and 55 million years ago, in the Eocene epoch of the Cenozoic Era, although this is contested, with some authors suggesting it was much later at around 35 million years ago.[2] If the collision occurred between 50 and 55 Ma, the Indian Plate would have covered a distance of 2,000 to 3,000 km (1,200 to 1,900 mi), moving faster than any other known plate. In 2007, German geologists suggested that the reason the Indian Plate moved so quickly is that it is only half as thick as the other plates which formerly constituted Gondwanaland.
The collision with the Eurasian Plate along the boundary between India and Nepal formed the orogenic belt that created the Tibetan Plateau and the Himalaya Mountains, as sediment bunched up like earth before a plow.
The Indian Plate is currently moving northeast at 5 cm/yr (2 in/yr), while the Eurasian Plate is moving north at only 2 cm/yr (0.8 in/yr). This is causing the Eurasian Plate to deform, and the India Plate to compress at a rate of 4 mm/yr (0.15 in/yr).
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The 9.3 moment magnitude 2004 Indian Ocean earthquake was caused by the release of stresses built up along the subduction zone where the Indian Plate is sliding under the Burma Plate in the eastern Indian Ocean, at a rate of 6 cm/yr (2.5 in/yr). The Sunda Trench is formed along this boundary where the Indo-Australian and Eurasian Plates meet. Earthquakes in the region are either caused by thrust faulting, where the fault slips at right angles to the trench; or strike-slip faulting, where material to the east of the fault slips along the direction of the trench.
Like all similarly large earthquakes, the December 26, 2004 event was caused by thrust-faulting. A 100 km (60 mi) rupture caused about 1,600 km (994 mi) of the interface to slip, which moved the fault 15 m (50 ft) and lifted the sea floor several meters (yards), creating the great tsunami.
On October 8, 2005, an earthquake of magnitude 7.6 occurred near Muzaffarabad, Kashmir, Pakistan killing more than 80,000 people, and leaving more than 2.5 million homeless.
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