Diamantina Fracture Zone western side of the Diamantina Fracture Zone at is another, larger pit, named Dordrecht Hole, with a north-south extent of 50 km. Its maximum depth is 7079 m at . "Dordrecht" was the name of a vessel of the Dutch East India Company, which explored the Australian west coast in 1619 and discovered the Houtman Abrolhos. The shallowest point in the area is the 1125-metre point in the Broken Ridge close to Ninety East Ridge. Diamantina Fracture Zone The Diamantina Fracture Zone is an area of the south-eastern Indian Ocean seafloor. It has a range of ridges and trenches. It
Ryukyu Trench gentle, reaching only 40-50° at 70 km depth. Ocean bottom seismography studies of the Ryukyu trench provide insight into the P-wave velocity structure of the area. In the northern part of the trench, several transects have been studied, including a profile of the back arc region parallel to the trench, a transect spanning the trench, fore arc and back arc region, and a transect spanning the Ryukyu volcanic arc. The transect perpendicular to the length of the trench images many distinct velocity layers. The sedimentary wedge created by subduction has four distinct layers with p-wave velocities of 1.8 km/s, 2.8-2.9