Indentation tectonics in the accretionary wedge of middle Manila Trench

Based on the multibeam morpho-tectonic analysis of the Manila Trench accretionary wedge and its indentation tectonics and the contrasting researches with other geological and geophysical data, three tectonic zones of the wedge are established, faulting features, tectonic distri- bution and stress mechanism for the indentation tectonics are analyzed, oblique subduction along Manila Trench with convergent stress of NW55° is presented, and the relation- ship of the ceasing of Eastern Subbasin spreading of South China Sea Basin to the formation of subduction zone of Ma- nila Trench is discussed. By the model analysis and regional research, it is found that the seamount subduction along Ma- nila Trench does not lead to the erosion of the accretionary wedge and the oblique subduction actually is a NWW- trending obduction of Luzon micro-plate that results from the NWW-trending displacement of the Philippine Sea plate.