oa Application of SAR Interferometry in Taiwan Crustal Deformation

The island of Taiwan is a product of the oblique collision between the Luzon arc and the Chinese continent margin. The present-day collision process of Taiwan is vigorous, as revealed by the high seismic activity and the active surface deformation. The deformations generated in this convergent system have been debated from a variety of geological and geophysical observations. In this study, we applied the InSAR technique to determine the co-seismic deformation of the central Taiwan area associated with the 1999 Chichi earthquake. The Mw 7.6, Chichi, Taiwan earthquake of 20 September 1999 produced reverse slip with left-lateral component along an 80 km-long surface rupture, the Chelungpu fault. Four ERS2-SAR images acquired before and after the event allow determination of the co-seismic surface displacement. This analysis reveals minor subsidence in the footwall block of the Chelungpu fault, with a maximum displacement of about 25 cm along the radar line of sight.