Surface Deformation of the Central Taiwan and Its Tectonic Implication of the Psi Analysis

Abstract

The Puli Basin, located between the Western Foothills and the Hsuehshan Range is the largest basin in the active orogeny in central Taiwan. South to the Puli Basin, a series of small basins spread along the NNE direction. Various tectonic models have been proposed in previous studies to interpret the formation of the Puli Basin. In this study, we aim to measure the deformation and to understand the tectonics of Puli Basin by the method of satellite remote sensing and field observation. We applied the Persistent Scatterer Interferometric SAR technique to monitor the surface deformation. Our result shows a relative lower LOS velocity in Puli Basin, which implies the change of depth of the subsurface basal detachment. A steep ramp along the detachment is proposed for the grown structure underneath the Puli Basin in this study. In order to interpret the mechanism of surface deformation in central Taiwan, we implement several forward models based on previous researches and our interferometric results and then compare our observations with accurate GPS and precise leveling data. These results can be compared with our field observations and with the recent seismicity data (20130327 and 20130602) to examine the activity and geometry of faults of this area, where a conjugate fault system below the basins was suggested. Due to the lack of evidence, the relationship between the conjugate system and the basin subsidence mechanism is hard to determine but may be the key to understand the tectonic activity in central Taiwan.