TECTONICS OF THE SOUTHEAST ASIAN PACIFIC REGION

Southeast (SE) Asia is composed of an assemblage of accreted terrains that record a long history of magmatism and collisional orogenesis. Proposed tectonic reconstructions for this region share many similar features, including long-term convergence along the Sunda Trench of Indonesia. This process has resulted in the formation of magmatic arcs which, together with accreted continental fragments, form the central core zone of the aseismic, tectonically-stable Sunda block of western SE Asia. In contrast, the eastern segment of SE Asia, including the Banda Sea, Molucca Sea, New Guinea, and the Philippines, is a diffuse plate boundary zone with multiple young subduction zones, continental micro-fragments, and back-arcs at various stages of maturity. The tectonic style in this eastern segment is dominated by subduction rollback and back-arc extension along the Banda arc. In this study we analyze a broad swath of geologic and geophysical data to determine the key structural elements and active tectonic processes in SE Asia and the surrounding region.