By the name, you can probably identify that it contains parts of India and Australia. But as with most tectonic plate boundaries, they often consist of both continent and ocean crust.
Continental drift means that plates are never idle. Over time, they move at a snail’s pace. For example, the Indo-Australian Plate moves at an average rate of about 3 centimeters per year.
Two plates separated but we often count them as one
The Indo-Australia plate is a major plate combining the Australian and Indian Plates. But they are widely considered to be two separate plates.
The Indo-Australia plate stretches from Australia to India. It also includes the oceanic crust from the Indian Ocean. The north-east side of the Australian plate converges with the Pacific Plate.
Long ago, Australia, India, and Antarctica were once connected as the supercontinent Gondwana. As part of the supercontinent cycle, India drifted apart moving northwards.
At about 58,900,000 km2, the Indo-Australia plate is the sixth largest plate tectonic boundary.
The Himalayan mountain range formation
About 50 million years ago, the Indian Plate and Eurasian Plate began colliding into each other lifting the Himalayan mountain range. To this day, these convergent plate boundaries are still uplifting building new mountain.
Because plate tectonic boundaries contain both oceanic and continental crust, the Indo-Australia plate contains the following features:
- Both countries of India and Australia are situated on the Indo-Australia plate.
- Sri Lanka, Fiji, Vanuatu and parts of New Zealand, Pakistan and Papua New Guinea are located on this plate
- The Indo-Australia plate contains majority of the Indian Ocean and Tasman Sea between Australia and New Zealand
The Australian Plate pushes into the Pacific Plate along the country of New Zealand causing violent earthquakes. For example, the magnitude 8.2 Wairarapa earthquake struck New Zealand in 1855 and was the largest recorded in New Zealand’s history.