Surface displacements of the Kanto plain, Japan, and subsurface structure: insight from persistent scatterer SAR interferometry

Abstract

We estimated recent surface displacements around the Kanto plain, Japan, by means of persistent scatterer SAR interferometry (PSInSAR) with ALOS/PALSAR data acquired from January 2007 to March 2011 and TerraSAR-X data acquired from March 2011 to November 2012. From the analysis of ALOS/PALSAR data, several subsidences due to groundwater extraction were identified. On the other hand, the analysis of TerraSAR-X data showed that displacement pattern was changed after the 2011 Tohoku earthquake: Our analysis revealed local uplift possibly due to visco-elastic rebound around Tokyo, where significant displacements had not ocuured just before the earthquake. Spatially-dense mapping of displacements also enables to understand the relationship with subsurface structure. The subsidence at the central Kanto plain and the local uplift around Tokyo are well correlated with the geomorphological feature. Our results showed the advantage of PSInSAR analysis for accurate mapping of surface displacements.