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Near Real-Time Ground Monitoring of Natural Hazards Using FAST-SAR

Fabien Albino1, Virginie Pinel1, Jean-Luc Froger2, Raphael Grandin3, Erwan Pathier1, Cecile Doubre4, Marie-Pierre Doin1, Franck Thollard1, Oliver Henriot1, Anne-Clothilde Legal1

  • Affiliations: 1 Univ. Grenoble Alpes, Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France 2 Université Jean Monnet - Faculté des Sciences et Techniques, Laboratoire de Géologie de Lyon : Terre, Planètes, Environnement - UMR CNRS 5276, France 3 IPGP, Univ. Paris Cité, CNRS, Paris, France 4 Institut Terre et Environnement de Strasbourg UMR7063, Université de Strasbourg/CNRS/ENGESS, 5 Rue René Descartes, Strasbourg, 67000, France

  • Presentation type: Poster

  • Presentation time: Friday 16:30 - 18:00, Room Poster Hall

  • Poster Board Number: 32

  • Programme No: 2.3.18

  • Theme 2 > Session 3

Abstract

The application of radar interferometry for near real-time ground monitoring of natural hazards, such asvolcanic activity and landslides, faces challenges including latency in acquiring SAR and external datasets, lengthy processing times, and the effective correction of error sources (e.g., atmospheric delays, topographic residuals, and unwrapping errors). The French National Service for Ground Deformation Monitoring (ISDeform) aims to provide ground displacement measurements using radar and optical imagery for active volcanoes and landslides in French territories. Here, we introduce FAST-SAR, a Fully Automated radar interferometry processing system tailored for Small Targets. This system is built on the NSBAS processing chain, which utilizes the small baseline subset method. To correct tropospheric noise, FAST-SAR makes use oflocal GNSS networks to generate tropospheric delay maps, which demonstrate superior performance compared to maps derived from global weather models such as ERA5 and GACOS. For correcting DEM errors, high-resolution topographic data from Pleiades and TanDEM-X DEMs are incorporated where available.For the time series, an incremental strategy is developed to only inverse recent acquisitions dates. FAST-SAR has been tested at multiple sites, including Piton de la Fournaise and Merapi volcanoes, as well as Harmalière and La Clapière landslides. For Piton de la Fournaise, the corrected InSAR time series show strong agreement with GNSS data, revealing inter-eruptive ground displacements that may be linked to the re-pressurization of the shallow magma reservoir. At La Clapière, the InSAR time series highlight acceleration of displacements rates during the winter months or rainy events, emphasizing the influence of external forcings.