Diamantina Fracture Zone Ridge Plateau. All these features are mirrored by corresponding topography on the other side of the Southeast Indian Ridge. Broken Ridge Plateau was formed at the ridge together with the Kerguelen Plateau. Diamantina Fracture Zone was first detected by and RV Argo in 1960. It is named after , which did further exploration in 1961. The Diamantina Deep is the zone's deepest location, located about 1 125 km West-South-West of Perth, Western Australia, at . This is not the deepest point in the Indian Ocean: the CIA's Physical Map of the World lists the Java Trench as such. On the
Hjort Trench Hjort Trench The Hjort Trench is a linear topographic depression south of Macquarie Island in the southwest Pacific Ocean. Geologically, the depression is considered to be the seafloor expression of an ocean-ocean subduction zone, where the Australian plate is thrusting beneath the Pacific Plate. As the southernmost portion of the Macquarie Ridge Complex, the Hjort Trench lies in an area of diagonal convergence produced by the transform fault evolution of the Emerald Fracture Zone. Frequent seismic events, most less than 20 km deep, characterize the transpression along this plate boundary. The deepest point of Hjort trench is approximately 6.3 km