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
Sumatra Trench in the reducing of the sediment thickness. The thickness is minimum at South Sumatra (1–2 km) and maximum at north Sumatra. The thickest sediment at north Sumatra can compare with the Makran Trench, which has the thickest sediment on Earth (7.5 km). Sediment thickness along the Sumatra Trench varies significantly, which is the result of fracture zones and fossil ridges' influence on basement topography. The thickness is a function of oceanic basement topography in some extent and this feature is extremely distinctive in the part between Simeulue and Siberut Islands (Central Sumatra region 2°N to 3°S) along the trench. This