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 km/s, 3.5 km/s, and 4.5–5 km/s. In the area of this transect, the wedge reaches a thickness of 9 km at 50 km from the trench. Beneath the wedge are several seismic layers within the oceanic crust. Separate ocean bottom seismography and multi-channel seismic studies provide insight into the structure of the northern end of the Ryukyu trench region. Features of note include a thick (7–12 km) low velocity (4–5 km/s) zone on the landward side of the trench, the existence of subducting paleo-arc crust near the top of the trench in contrast to simple oceanic crust located at the