InSAR-driven landslide hazard assessment along highways in hilly regions: A case-based validation approach

This is the authors' abstract. We don't add key points for this paper.

Highway landslides in hilly regions pose significant risks to transportation infrastructure. Current monitoring systems, confined to jurisdictional boundaries, neglect cross-administrative slopes, creating systemic gaps in hazard management. This oversight is exacerbated in densely vegetated areas lacking standardized detection protocols, where external landslides may trigger destructive debris flows impacting highways. A two-stage framework is proposed in this work. Failure mechanism of failure landslides, located beyond the jurisdictional redline of a highway, are first analyzed based on small baseline subset synthetic aperture radar interferometry (SBAS-InSAR). The obtained deformation thresholds together with SBAS-InSAR are then used to quantify pre-failure deformation and identify landslide risk along the same highway. Results show that vegetation destruction and rainfall are primary triggers for the studied landslide and subsequent debris flows. SBAS-InSAR revealed an annual deformation threshold of 21.4–32.8 mm/year. High-risk slopes within 500 m of the highway with sparse vegetation require prioritized monitoring during rainy seasons. This approach offering actionable criteria for authorities to monitor extra-jurisdictional slopes. By integrating failure mechanism analysis with deformation thresholds, the study bridges jurisdictional gaps in infrastructure risk management, enhancing resilience against previously overlooked cross-boundary hazards.