The Sunda Trench, earlier known as, and sometimes still indicated as the Java Trench,[1] located in the northeastern Indian Ocean, with a length of 2,600 kilometres (8,500,000 ft) and a maximum depth of 7,725 metres (25,344 ft) (at 10°19'S, 109°58'E, about 320 km south of Yogyakarta), is the second-deepest point in the Indian Ocean after Diamantina Trench, which is 8,047 metres deep. It stretches from the Lesser Sunda Islands past Java, around the southern coast of Sumatra on to the Andaman islands, about 300 km off the coasts of Java and Sumatra, and forms the boundary between Indo-Australian Plate and Eurasian plate (more specific, Sunda Plate), is part of the Pacific Ring of Fire and a ring of oceanic trenches around the northern edges of the Australian Plate.
There is scientific evidence that the recent earthquake activity in the area of the Java Trench could lead to further catastrophic shifting within a relatively short period of time, perhaps less than a decade.[2] This threat has resulted in international agreements to establish a tsunami warning system in place along the Indian Ocean coast.[3]
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For about half its length, off of Sumatra, it is divided into two parallel troughs by 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.[4]
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 world wide scientific field exploration of the world's ocean floor and sub-oceanic crustal-structure. Bomb-sounding, echo-train analysis and manometer were some of the techniques used to determine the depth of the trench. The research contributed to an understanding of the subduction characteristic of the Pacific margins.[5]
Various agencies have explored the trench in the aftermath of the 2004 earthquake, and these explorations have revealed extensive changes in the ocean floor.[6]
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