Geography of Indonesia is responsible for the creation of the Sunda Trench, and mountain ranges across Sumatra, Java, and the Lesser Sunda Islands. Many great earthquakes occurred in the vicinity of the fault, such as the 2004 Indian Ocean earthquake. Mount Merapi, located in the Java portion of the megathrust, is the most active volcano in Indonesia and is designated as one of world's Decade Volcanoes due to the hazard it poses to the surrounding populated areas. The northern part of Sulawesi and Maluku Islands lie on the convergence of Sunda Plate and Molucca Sea Plate, making it an active tectonic region with
Oceanic trench to dispose of sediment. An evolution in trench morphology can be expected, as oceans close and continents converge. While the ocean is wide, the trench may be far from continental sources of sediment and so may be deep. As continents approach each other, the trench can fill with continental sediments and become shallower. A simple way to approximate when the transition from subduction to collision has occurred is when the plate boundary previously marked by a trench is filled enough to rise above sea level. Accretionary prisms grow in two ways: by frontal accretion, whereby sediments are scraped off the