West Java is the Indian Ocean. Unlike most other provinces in Indonesia which have their capitals in coastal areas, the provincial capital, Bandung, is located in the mountainous area in the centre of the province. Banten Province was formerly part of West Java Province but was created a separate province in 2000. West Java, in the densely populated western third of Java, is home to almost 1 out of every 5 Indonesians. West Java and Banten provinces, as a part of the Pacific Ring of Fire, have more mountains and volcanoes than any of the other provinces in Indonesia. The vast volcanic
Sumatra Trench to 350 km. The width at Sumatra trench is controlled by sediment input and accretion rate and history. One distinguishing feature of the Sumatra subduction zone is that it has a relatively 120–140 km accretionary prism and a deep forearc basin (so does the rest of the whole Java subduction zone). However it does vary along the trench. The prism is broad and has a relatively shallow surface slope in the northern part, becomes steep and narrow at the central part, then becomes steep and narrow in the southern area. The inner part of the prism forms a NW-SE arc