The application of InSAR DEMs for volcanic hazard assessments at Mount Taranaki, New Zealand

Abstract

Interferometric Synthetic Aperture Radar (InSAR) can be used to detect ground motion but also processed further to generate Digital Elevation Models (DEMS). Sentinel-1 images are acquired continuously, and data is made available free of access in near real time making it a valuable tool for Earth observation and volcanic hazard assessment. Mass flow simulations require up to date DEMs for the results to be integrated in volcanic hazard management and mitigation. This study investigates the applicability of InSAR generated terrains as information and data with respect to volcanic hazard analysis as well as the input data in simulating block- and-ash flows (BAFs) following the collapse of volcanic domes on Mount Taranaki, New Zealand, using the Titan2D simulation toolkit. Results show that the accuracy of Sentinel-1 InSAR generated DEMs are limited for volcanic hazard analysis in areas of dense vegetation and steep topography due to temporal decorrelation and geometrical distortions. Together, these conditions introduce major differences in inundation extent and thickness distribution of simulated flows yet can provide some indication of flow impact which may be of relevance for rapid decision making in response to rapidly changing volcanic landscapes.