Comparison of satellite-based InSAR methods for monitoring geothermal areas at Rotokawa: PS versus SBAS

Abstract

This study utilises freely available Sentinel-1 satellite InSAR data to map surface deformation at the Rotokawa thermal area between 2014 - 2024. Three InSAR methods are used to examine the area: PS InSAR (StaMPS), and two SBAS methods (GMTSAR and LiCSBAS). While StaMPS provides the best resolution to localised deformation, both SBAS methods have the advantage of providing total coverage across the survey area. LiCSBAS can efficiently process very long time series (i.e. 10 years) and may be applied to very large areas (> 1000 km2
). A disadvantage of LiCSBAS is that it may not resolve localised areas of surface deformation, e.g. small subsidence bowls (< 200 m radius). This is a limitation of the method, which utilises a coarser grid and averages signals over a wider area.