Nonlinear Modeling of Subsidence From a Decade of InSAR Time Series

Abstract

We present a model of ground subsidence due to soil consolidation within coastal reclaimed land constructed in early 2001, in Busan, South Korea. We estimate 42 cm of maximum subsidence during the period of interferometric synthetic aperture radar observations, and a maximum of 1 m or more subsidence, since the end of the construction phase of the reclamation project. A hyperbolic model was used to relate the three independent time series and to estimate the nonlinear behavior of subsidence. The model estimates a maximum subsidence rate and acceleration of −5.7 cm/year and 1.1 cm/year2, respectively. The decomposition of vertical and east-west horizontal motion using the Sentinel-1 dataset indicates relatively weak partial horizontal displacement as well as substantial vertical deformation overall. The long-term time series analysis indicates ongoing ground subsidence, although almost two decades have passed since the completion of reclamation.