Indian Plate
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The India 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, it fused with the adjacent Australian Plate. It is today part of the major Indo-Australian Plate, and includes the subcontinent of India 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 India Plate split from Madagascar. It began moving north, at about 20 cm/yr (8 in/yr) [1], and began colliding with Asia between 50 and 55 million years ago, in the Eocene epoch of the Cenozoic Era. During this time, the India Plate covered a distance of 2,000 to 3,000 km (1,200 to 1,900 mi), and moved faster than any other known plate. In 2007, German geologists determined that the reason the India Plate moved so quickly is that it is only half as thick as the other plates which formerly constituted Gondwanaland. [2]
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 India 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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[edit] 2004 Indian Ocean earthquake
The 9.3 magnitude 2004 Indian Ocean earthquake was caused by stress in the subduction zone where the India 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 faultline slips at right angles to the trench; or strike-slip faulting, where material to the east of the faultline 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.
[edit] 2005 Kashmir earthquake
On October 8, 2005, an earthquake of magnitude 7.6 occurred near Muzaffarabad, Kashmir, Pakistan killing at least 60,000 people, and leaving more than 2.5 million homeless.
[edit] See also
- Indian subcontinent
- Convergent boundary
- Geology of India
- List of tectonic plates
- List of tectonic plate interactions
- Paleogeography
- Plate tectonics
[edit] Notes
[edit] External links
- The collision of India and Asia (90 mya — present), by Christopher R. Scotese, from the Paleomap Project. Retrieved December 28, 2004.
- Magnitude 9.0 off W coast of northern Sumatra Sunday, December 26, 2004 at 00:58:49 UTC: Preliminary earthquake report, from the U.S. Geological Survey. Retrieved December 28, 2004.
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