Dordrecht Deep is part of which Indian Ocean fracture zone?

Dordrecht Deep is part of the Diamantina fracture zone in the Indian Ocean.

The feature lies within the Diamantina Trench, southwest of Perth, Western Australia. The trench occupies the eastern section of the much larger fracture zone, a long seafloor feature extending roughly 1,900 kilometres from the Ninety East Ridge toward the Naturaliste Plateau.

A common mix-up is to answer “Diamantina Trench” rather than “Diamantina fracture zone.” The trench is the immediate deep, while the question asks for the broader geological structure. Romanche Trench belongs to the Atlantic, and Mendocino fracture zone is off western North America, so neither fits.

Dordrecht Deep was long considered one of the Indian Ocean’s deepest points. Later high-resolution mapping by the Five Deeps Expedition measured it at about 7,019 metres, confirming that the Sunda Trench—not the Diamantina fracture zone—contains the ocean’s deepest point.