Soil liquefaction at water front area associated with 2011 Tohoku earthquake; Insight from DInSAR analysis

Abstract

We performed Differential Interferometric Synthetic-Aperture Radar (DInSAR) analysis to the SAR images before and after the 11th March 2011 Tohoku-Oki earthquake to estimate surface displacement associated with soil liquefaction at waterfront along Tokyo bay. Because it has been reported that land subsidence and the damage of infrastructure caused by soil liquefaction was severe, however it is difficult to observe the surface displacement by ground-based observation systems due to the wide range of the damaged area. Here, we try to detect local surface displacement especially in waterfront area along Tokyo bay via DInSAR analysis. We conclude that the estimated local surface displacements are associated with soil liquefaction, because this detected local displacement occurred in the direction away from the satellite, which is assumed to be subsidence, is consistent with sand boiling distribution after earthquake. Our result demonstrates that soil liquefaction was severely occurred at old artificially filled ground located far from coastline rather than new one located near coastline. DInSAR analysis would be one of the effective tools to investigate the distribution and the degree of soil liquefaction rapidly after the occurrence of earthquake.