Identification of accretionary wedge at Sumatra subduction zone using 2D seismic reflection

Abstract

This research is focusing on structure at Nias Islands subduction zone. Subduction zone Sumatra is the collision zone of Eurasia continental plate and Indo-Australia oceanic plate. Prior to the establishment of the subduction zone there is an event of the making of continental crust in which in this research area is marked by Wharton Fossil Ridge. An odd feature of the Sunda subduction zone is the non-volcanic forearc ridge that comes up raised sea level assemble a lot of islands betwixt the trench and the mainland. The forearc ridge is the cap of a chunky sequence of sediments and sections of sea floor, known as the accretionary wedge, that are folded, faulted and plastered into the upper plate. Accretionary wedge structure which has the melange rock characteristics because of the plates’ subduction, The accretionary wedge could be intrepred using seismic reflection data with characteristic reflector doesn’t formed or visible. The islands offshore southwestern Sumatra might have a akin origin. The most appropriate study of these is Nias, which its southwest coastline is 90 km form the subduction deformation front and 20 km above the dipping plate interface. Southwest of Nias, the oceanic seafloor is dipping at a homogeneous angle 6° to 7° against Nias for a horizontal distance of 25 km beneath the accretionary wedge, where it attaints a depth of just over 10 km. In this research it has been done 2D seismic reflection data processing and the interpretation of the Wharton fossil ridge establishment, subduction zone, and accretionary wedge.