Moho depth derived from gravity data in the Taiwan strait area

Abstract

We have constructed a regional Bouguer gravity anomaly map using marine and land data from Taiwan and the Chinese province of Fuchien, as well as SEASAT altimetry-derived gravity data for the Taiwan Strait and its surrounding area. The map shows isogals trending generally in a NE-SW direction, conforming with the overall shallower geological strike of the strait. Removing gravity effects generated by the water layer and seafloor topography, the regional Bouguer gravity anomaly is obtained, reflecting the subsurface structure. Moho depth is then computed by the Parker-Oldenburg iterative method from the regional Bouguer gravity data set. Over the strait area, the geometry of the Moho relief is smooth with an average depth of about 30 km, except for the Penghu uplift. Moho depth is shallower in the Taiwan Strait and thickens toward both sides of the strait. The relatively shallower Moho depth, reaching up to 28 km, is convex upward underneath the Penghu uplift.