Uplift of Tainan Tableland (SW Taiwan) revealed by SAR Interferometry

Interferometric processing of five SAR-ERS images reveals uplift of the Tainan Tableland (SW of Taiwan) during the period 1996–1998. The maximum measured ground motion for these two years is 2.8 cm along the radar line of sight towards the satellite, indicating for the displacement vector a vertical component of 3.2 cm, and a horizontal component of 1.6 cm towards the WSW considering additional information from GPS data. The reconstructed displacement field is consistent with the geological interpretation of the Tainan Tableland as an actively growing anticline connected to the Taiwan fold-and-thrust belt. This implies that the deformation front is located farther west than usually assumed in the Tainan area. The large Tainan city is thus located in an active deformation zone. Seismic hazard assessment is however difficult because the mechanisms and kinematics are not known in detail.