New insight on the deformation along the southern Java forearc

American Geophysical Union Fall Meeting 2012

New insight on the deformation along the southern Java forearc

Mukti, M.M.* S.C. Singh* I. Deighton**H. Permana***
* Geosciences Marines, IPG Paris
** TGS
*** Geotek – LIPI

Abstracts
The new seismic dataset in south Java resolved detailed structures of the southern Java forearc. The plate interface expressed as irregular surface in the western part and rather a continuous smooth boundary in the eastern area. This observation coincides with the higher uplift of the western part of the forearc high. Cluster of shallow earthquakes can be observed near the western part of Java trench. Deformation of the forearc high is more intense in the west compared to that in the east. This coincides with higher uplift of the western part of the forearc high, thus complicated the structures. However, the landward portion of compressional structures still can be observed within the forearc basin sediments. Backthrusting of the accretionary wedge can be observed. The higher uplift of the forearc high has separated the Pliocene sediments deposited in the forearc basin and in the forearc high. Therefore, we interpret this uplift developed after the Pliocene. A morphological break of the top of the accretionary wedge can be recognized to the south of the forearc high, indicates the boundary between the forearc high thrust and those in the frontal wedge. We interpret that the compressional structures developed in the southern Java forearc exhibit similar features with those in the southern Sumatra forearc. However, some part of the forearc high has been abruptly deformed possibly due to the subduction of higher relief in the oceanic plate, similar to the Roo Rise.