Operationalizing InSAR and Pixel Offset Time Series Methodologies for Landslide Monitoring

Time-series InSAR techniques may be able to greatly increase our landslide monitoring capabilities, but in many landslide-prone areas, high rates of temporal decorrelation due to landslide movement and the presence of steep, vegetated terrain limit the utility of many InSAR techniques. Recent advances in both time-series InSAR techniques and pixel offset tracking techniques have however begun to overcome these limitations. In this study, we use an SBAS InSAR technique that highlights local deformation and an SBAS-like pixel offset tracking technique to remotely monitor over 800 landslides within a 10,000 km² region of New Zealand’s North Island. Even though landslide movements rates in our study area range from 0.01 to 10 m/yr and the entirety of study area suffers from high rates of temporal decorrelation, we have found that our analysis framework is capable of monitoring both landslide activity states and movement rates. The results of this analysis are now being used to estimate the sediment contribution of landslides to local rivers, and to help prioritize the administration of conservation funding that seeks to improve the health of New Zealand’s rivers. In addition to our results, our reliance on open-source software and globally available remote sensing data ensure that our analysis can also be efficiently conducted in other areas that experience high rates of temporal decorrelation.