SBAS-InSAR Detection of Active Landslides at Røsnæs
Session
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Abstract
This work investigates whether SBAS-InSAR time-series methods can retrieve ground motion signals over natural terrain in Røsnæs where EGMS observations are limited or absent.
Sentinel-1 SAR data from December 2018 to January 2024 were processed using HyP3 and MintPy. A total of 487 ascending and 498 descending interferometric pairs were processed to derive line-of-sight, vertical, and east-west displacement. The strongest signals occur within mapped landslide polygons, including areas without EGMS observations. Agreement between east-west displacement velocity and vertical changes from a 2007–2023 DEM of Difference supports their interpretation as ground motion.
The strongest westward rate, 12 cm/y, occurred from October 2019 to July 2020, coinciding with increased precipitation and a shallower water table. SBAS-InSAR can complement EGMS for characterizing landslide ground motion.
These findings are especially relevant in the context of climate change, in which the potentially warmer and wetter future climate in Denmark will likely lead to more landslide activity in the near future.
Målgruppe
The target group is participants at Kortdage 2026 working as GIS & geodata specialists, remote sensing scientists, climate change & geohazard researchers, geotechnical engineers, state authorities (infrastructure), policy advisors, and private consultants.
Yderligere uddybning af abstract
The Miami InSAR Time-Series software in Python (MintPy) is an open-source package for SBAS-InSAR time-series analysis that reads a stack of and produces two-dimensional displacement time series in satellite line-of-sight geometry. It is compatible with interferograms generated on-demand using Alaska Satellite Facility's (ASF) Hybrid Pluggable Processing Pipeline (HyP3). In this work, the interferogram generation process was automated through HyP3, while subsequent time-series analysis with MintPy was conducted using the Jupyter book provided by OpenSARLab.
To investigate potential relationships between ground motion and environmental conditions in a spatiotemporal context, the SBAS-derived results were compared with geomorphological (topographic) changes derived from a DEM of Difference (DoD) and hydrological data from the period. The DoD was calculated from the current Danmarks Højdemodel – Terræn digital elevation model (DEM) and the historical 2007 version provided by Dataforsyningen. The hydrological data (simulated water table depth (WTD) and gridded observed precipitation) was taken from the national hydrological model DK-model HIP and used to assess the temporal relationship between rainfall, WTD and detected displacement signals.
Results demonstrate that SBAS method can retrieve displacement signals over natural terrain in the Røsnæs coastal slope, including areas where EGMS observations are limited or absent. Furthermore, results suggest that ground motion is not constant through time, with the strongest displacement occurring during a period with increased precipitation and shallower WTD and its onset coinciding with one of the wettest months in recorded history.
