Measurements of soil compaction rate by using JERS-1 SAR and a prediction model

The soil compaction rate in a reclaimed land has been estimated by using the Japanese Earth Resources Satellite 1 (JERS-1) synthetic aperture radar (SAR) two-pass differential interferometry (DInSAR) and magnetic probe extensometer (an accuracy of ±1 mm) from 42 ground stations. Twelve JERS-1 SAR interferometric pairs were acquired in the study area. We applied a soil compaction prediction model based on a hyperbolic method using the ground truth data and the DInSAR measurements. The hyperbolic model fitted well to the ground measurements with an rms error of 1.65 cm. The rms error of the model driven by DInSAR measurements was 2.24 cm. The two model results agreed well, showing a difference of 8.1% (12.9 cm) in permanent settlement that is defined as the amount of vertical subsidence as time goes to infinity. A two-dimensional (2-D) subsidence map was constructed from five qualified pairs. The correlation coefficient R between the radar measurements and the ground truth data was 0.87 with an rms error of 1.44 cm. The results demonstrate that the L-band DInSAR combined with a prediction model is useful for geotechnical applications.