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
Japan Trench within the Japan Trench consist mainly of highly localized clay-rich material. The subducting Pacific Plate creates basins along the ocean floor of the Japan Trench, accommodating the deposition of fine-grained turbidites and interseismic sediment deposits through turbidity currents. These turbidites preserve the sediment deposits as a geologic record of past large earthquakes by indicating the change in sediment deposition through sediment gravity flow. The small deep-sea basins with high sedimentation rates found along the Japan Trench fault line pose favorable environmental conditions for the studying of turbidite paleoseismology. During an exploration to the Japan Trench on January 1, 1999, a