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
Chapada Diamantina 25 km wide and exposes the sedimentary rocks of the Paraguaçu group. At the contact there are two different rock groups exposed one being the Chapada Diamantina and the Paraguaçu, with the Chapada Diamantina overlaying the Paraguaçu group. The two rock groups not only in elasticity but in composition as well. The Chapada Diamantina is composed primarily of sandstone, pelites and diamond bearing conglomerates. The Paraguaçu is composed of fine-grained sandstones, siltstones and argillites. The rocks of the Paraguaçu are softer and therefore more susceptible to weathering and folding. It is the folds in the Paraguaçu that allows for the