Tomographic evidence for the Eurasian lithosphere subducting beneath south Taiwan

A tomographic image of the crust and upper mantle beneath the Taiwan Island as derived from local, regional and teleseismic data simultaneously revealed a high-velocity zone from the surface down to a depth of 300 km, locating beneath south Taiwan ( to the south of latitude 24 degrees N). We interpret this high-velocity zone to be the subducted Eurasian lithosphere. Our result is different from a global tomography study that shows the Eurasian plate subducting beneath most part of the Taiwan Island down to 670 km depth. This down-going model of the Eurasian lithosphere implies that the tectonic framework of Taiwan has been changing from subduction in the south to collision in the north, which provides geophysical evidence supporting the previous proposed models. The subducted Eurasian lithosphere colliding with the subducted Philippine Sea plate would have contributed to the mountain building, active seismicity and crustal deformation in the study region due to the lower part of the Eurasian continental plate subducted beneath south Taiwan.