Sunda Trench

Oceanic crust is formed at the mid-oceanic ridge, while the lithosphere is subducted back into the asthenosphere at trenches like that of Sunda Trench. The Sunda Trench, earlier known as and sometimes still indicated as the Java Trench, is an oceanic trench located in the Indian Ocean near Sumatra, formed where the Australian-Capricorn plates subduct under a part of the Eurasian plate. It is 3,200 kilometres (2,000 mi) long with a maximum depth of 7,290 metres (23,920 feet). Its maximum depth is the deepest point in the Indian Ocean. The trench stretches from the Lesser Sunda Islands past Java, around the southern coast of Sumatra to the Andaman Islands, and forms the boundary between the Indo-Australian plate and Eurasian plate (more specifically, Sunda plate). The trench is considered to be part of the Alpide belt as well as one of oceanic trenches around the northern edges of the Australian plate.

Sunda Trench and the epicenters along it, due to the subduction process where the India Plate subducts under the continental fragments of the eastern microplates. In 2005, scientists found evidence that the 2004 earthquake activity in the area of the Java Trench could lead to further catastrophic shifting within a relatively short period, perhaps less than a decade. This threat has resulted in international agreements to establish a tsunami warning system in place along the Indian Ocean coast.