ABSTRACT
The archipelago is affected by two continental masses: Asia in the northern hemisphere and Australia in the southern hemisphere. Dutch geologists and several other scientists believe that friction between the tectonic plates of these two continents has created these folded arcs of islands in Indonesia, with active mountain building, volcanism, and periodic seismic upheavals (Fisher, 1966; van Bemmelen, 1949). Another also widely accepted theory considers the islands as parts
of the arc of volcanoes and fault lines, belonging to the Pacic Ring of Fire, circling around the Pacic basin.
