Detection of 3D Land Displacement After the Great East Japan Earthquake In 2011 From Multi-Temporal SAR Images And GPS Data

This paper presents the results of estimating land displacement of the areas after an earthquake by utilizing synthetic aperture radar (SAR) time-series images. We selected the nuclear power station in Fukushima Prefecture, Japan, damaged by the Great East Japan Earthquake in 2011, and the tsunami triggered by the earthquake. The still ongoing displacement of the areas, especially the underground frozen soil wall installed, should be quantitatively estimated. In usual, the displacement estimated by persistent scatterer interferometry (PSI)[1,2] is obtained only in the radar line-of-sight (LOS) direction. We estimated three-dimensional displacement velocities by applying the least-squares method to the results from PSI and Global Positioning System (GPS) data. We used 13 and 17 ALOS-2/PALSAR-2 images acquired on the ascending and descending orbits, respectively in addition to the displacement data measured at 10 GPS stations. The obtained results show that local displacement is estimated, and the displacement along the frozen soil wall is different from the neighboring areas. Consequently, it was shown that combining PSI results and geodetic deformation measurements is effective for monitoring land subsidence.