Indo-Australian Plate

The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and surrounding ocean, and extends northwest to include the Indian subcontinent and adjacent waters. It was formed by the fusion of Indian and Australian plates 43 million years ago. Recent studies, and seismic events such as the 2012 Indian Ocean earthquake, suggest that the Indo-Australian Plate may be in the process of breaking up into two separate plates due primarily to stresses induced by the collision of the Indo-Australian Plate with Eurasia along the Himalayas. The eastern part (Australia) is moving northward at the rate of 5.6 cm per year while the western part (India) is moving only at the rate of 3.7 cm per year due to impediment by Himalayas. This differential movement is resulting in the compression of the plate near its center at Sumatra and a potential division into Indian and Australian Plates . The two protoplates or subplates are generally referred to as the Indian Plate and the Australian Plate.

A third Capricorn Plate may also be separating off of the west side of the Indian subplate.