Arc-continent collision between Eastern Sunda Arc (Banda Arc) and Southwest Australia continent formed the southern boundary of the tectonic elements. This collision zone is part of the evolutionary stages of young or early and more to resemble aspects of normal trench-arc system.
In the eastern part of Sumba Island, Indian Ocean crust has a complete experience of intense subduction and Australia now has been raised above the Banda Arc due this. To the west of the collision zone, Sunda Arc moved to the edge of continental Southeast Asia which make up one of the classic collision system features, in which the crust of the Indian Ocean-Australian (about >150 Ma) forces down along the Sunda trench, given that the Indian Ocean Plate, Australia moved northward relative to the Eurasian Plate with a velocity of about 7.5 cm/year (according to Curray, 1989). The island of Java, Bali, Lombok and Sumbawa expected forming this through the formation of the volcanic arc on the southern edge of Sundaland that initially passive. Sumba represents the bedrock that uplifted front of the arc and was trapped in front of the arc current basin (Reed et al., 1986). Some evidence suggests that the development of Sumba geology can be parallel correlated with Doang Borderland located at the end of the edge of the Sunda Shield (Wytze et al., 1991). However, Lombok front arc basin lies to the west of Sumba marked by the opening structures on certain stratigraphy horizon.
Transition zone Sunda-Banda arc is clearly recorded the existence of two straight thrust fault zone, both located in the front of the arc itself. One is represented by Savu fault (thrust type), and the other were behind the arc is called Flores back arc fault (back-arc thrust type). Both systems are connected (Silver and Reed, 1987). Area behind the arc shows laterally discontinuous zones of the back arc fault structures and produced younger accretionary wedges.
Timor Island is located outside the non-volcanic arc islands of Indonesia, between the Australia plates that move toward the north and the outer Banda arc as part of the Eurasian plate. The Timor Island is made by deformation of the northern Australia plate which had being thrust faulted, especially the southern part around Timor Trough.
The Non-volcanic arcs consist of the underwater ridge of Java Trench, Timor Island, Tanimbar, Kei and Seram up to the east. During the Tertiary age, continuous trench system was fairly active in northwestern Sumatra, Java Trench, the Lesser Sunda Islands, Timor, Tanimbar, Kei and Seram, accompanied by active volcanic subduction that can be found on the West Coast of Sumatra, South Coast of Java, Lesser Sunda Islands (Katili, 1990).
Component of plate tectonics collision involved in this, namely the Asian plate lithosphere that appear shaped by the continental crust (Sunda Craton), sea-marginal (marginal sea) of the Banda Sea, and Australian-Irian lithosphere plate (Gondwana), made by the oceanic crust Indian and Australian continental crust include elements from the island of New Guinea, Buru, Obi and others.
Tectonic evolution that began at the age of the Upper End of Perm, Middle Jurassic, Early Cretaceous until the Late Cretaceous and Neogene basin formation resulting from Paleozoic basin which had trending oriented northwest-southeast direction which then formed again (overprinting) by later Mesozoic basin of northeast-southwest trending direction. Meanwhile, the sinistral transform fault was rejuvenated by Neogene normal fault were related both sides (N. Sitompul, S, Wijanto, J., Purnomo, 1993).
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