Sunda Trench an underwater ridge, and much of the trench is at least partially filled with sediments. Mappings after the 2004 Indian Ocean earthquake of the plate boundary showed resemblance to suspension bridge cables, with peaks and sags, indicative of asperity and locked faults, instead of the traditional wedge shape expected. Some of the earliest exploration of the Trench occurred in the late 1950s when Robert Fisher, Research Geologist at the Scripps Institution of Oceanography, investigated the trench as part of a worldwide scientific field exploration of the world's ocean floor and sub-oceanic crustal-structure. Bomb-sounding, echo-train analysis and manometer were some of
Puerto Rico Trench assigned to genus "Peniagone". The other individual, a small crustacean, is tentatively identified as a "munnposid" "isopod", based on morphology and similar walking and jumping movements observed for other hadal "munnopsid" "isopods". Because these individual were not collected, it is not possible to obtain species-level identifications. However, these sightings likely exceed the deepest known records for genus "Peniagone" and family "Munnopsidae". Puerto Rico Trench The Puerto Rico Trench is located on the boundary between the Caribbean Sea and the Atlantic Ocean. The oceanic trench is associated with a complex transition between the Lesser Antilles subduction zone to the south and