HMAS Diamantina (K377) deepest known part of the Indian Ocean on 7 February 1960, which was named Diamantina Deep after the ship. Based in Fremantle, Western Australia, "Diamantina" remained in service as an oceanographic vessel until 1980; she briefly interrupted these duties in March 1963, escorting the royal yacht during Queen Elizabeth II's tour to Australia. "Diamantina" paid off from the RAN on 29 February 1980, and was the last World War II-era frigate to serve Australia. "Diamantina" was handed over to the Queensland Maritime Museum to be permanently berthed in the South Brisbane Dry Dock located on the Brisbane River at South
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