- Australian Plate (Wikipedia)
The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately 100 million years ago when India broke away and began moving north. Australia and Antarctica had begun rifting by 96 million years ago and completely separated a while after this, some believing as recently as 45 million years ago, but most accepting presently that this had occurred by 60 million years ago.
- Pacific Plate (Wikipedia)
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million km2 (40 million sq mi), it is the largest tectonic plate.
- Tonga Plate (Wikipedia)
The Tonga Plate is a small southwest Pacific tectonic plate or microplate. It is centered at approximately 19° S. latitude and 173° E. longitude. The plate is an elongated plate oriented NNE - SSW and is a northward continuation of the Kermadec linear zone north of New Zealand. The plate is bounded on the east and north by the Pacific Plate, on the northwest by the Niuafo’ou Microplate, on the west and south by the Indo-Australian Plate. The Tonga plate is subducting the Pacific plate along the Tonga Trench. This subduction turns into a transform fault boundary north of Tonga. An active rift or spreading center separates the Tonga Plate from the Australian Plate and the Niuafo’ou microplate to the west. The Tonga Plate is seismically very active and is rotating clockwise.
- The Kermadec Plate is a long and narrow tectonic plate located west of the Kermadec Trench in the south Pacific Ocean. Also included on this tectonic plate is a small portion of the North Island of New Zealand and the Kermadec Islands. It is separated from the Australian Plate by a long divergent boundary which forms a back-arc basin. This area is highly prone to earthquakes and tsunamis.