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
Tonga Trench midway between two large oceanic plateaux north and south of the Tonga Trench respectively: Manihiki to the north and Hikurangi to the south. These plateaux once formed part of the Ontong Java-Manihiki-Hikurangi large igneous province (LIP). Spreading between the plateaux ceased when Hikurangi collided with the Chatham Rise east of New Zealand at 86 Ma. The western end of the Osbourn Trough is bounded by the Tonga Trench and its eastern by the Wishbone–East Manihiki Scarp. In between the Osbourn Trough is divided into three segments separated by dextral offsets. Near the Tonga Trench the bathymetry of these structures is