Long-range ground deformation measurement using interferometric synthetic aperture radar data on both up-going and down-going orbits

Abstract

Interferometric Synthetic Aperture Radar (InSAR) is a technique for mapping subtle surface deformations over a two-dimensional areas with high spatial resolution. The objective of this study is to evaluate the capability of InSAR analysis using both up-going and down-going orbits data for monitoring the long-range ground deformation caused by the environmental disaster. Differential InSAR (DInSAR) analysis and InSAR time series analysis were performed around disaster areas of the Kirishima Mountains in Japan (Fig. 1). The data used in this study were images from the Advanced Land Observation Satellite/Phased Array Synthetic Aperture Radar (ALOS/ PALSAR) observed from 2007 to 2011. We performed DInSAR analysis and InSAR time-series analysis with a commercial software and attempted to precisely estimate vertical and horizontal displacements by using the vector composition method from the observation data of both orbits. The results show that InSAR analysis is effective for the disaster monitoring of volcanic eruptions. Uplift and subsidence were detected around the Kirishima Mountains before the last eruption on January 26, 2011. This result suggests that long-range InSAR analysis has a capability to detect the symptoms of volcanic eruptions.