Examining the Feasibility of Sentinel-1 InSAR data for landslide monitoring and failure forecasting in western Canada.

Date

2024-01-03

Authors

Blenman, Peter

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Abstract

Landslides are geological hazards that significantly threaten human life, infrastructure, and biotic habitat in areas with steep slopes. Precursory signs of a landslide can be undetectable or non- existent, making the evacuation of residents unlikely. The ongoing climatic cycles and geological triggers imposed on regions susceptible to landslides exhibit long-term ground movement superimposed with accelerations due to seismicity or precipitation. Landslide monitoring and forecasting aims to understand the structural dynamics of the slide accelerations to estimate when there will be a catastrophic failure. The thesis explores the potential of InSAR technology for monitoring slope movement in the western Canadian Cordillera. The study takes a two- pronged approach: first, investigating the capability of the technique to detect movement on slopes that have already undergone previous landslide activity, focussing on the Garibaldi Volcanic Complex (GVC) as a case study, and second, analyzing five sites that have recently experienced landslides to determine if InSAR technology could have forecasted the failures. The InSAR results presented in the thesis show that ground displacement occurred on the slopes of all the study sites, which corresponded with previous landslide activity. However, InSAR results collected during winter months were less detailed and frequent than those collected using a seasonal approach. The forecasting study discovered that all the sites displayed signs of preceding movement on the slopes, which were successfully detected by InSAR. Furthermore, each site encountered extreme weather conditions, resulting in catastrophic failure. The Elliot Lake and Ecstall River sites experienced seismic activity the same afternoon as the landslide events, potentially connected to glacial loss and retreat. Results obtained during snowfall were less reliable than the summer acquisitions. iv The results from the thesis demonstrate that the Sentinel-1 mission's temporal resolution is inadequate for creating a real-time monitoring system for landslide-prone slopes in western Canada. Factors that trigger landslide acceleration, such as precipitation, seismicity, and geological processes, can occur over decades or hours. Hence, the primary role of Sentinel-1 in landslide monitoring is identifying large-scale moving slopes. Future InSAR platforms could provide a promising solution with high temporal resolution, making landslide forecasting and monitoring a reality.

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Keywords

Risk assessment, Landslides, Climate change, InSAR, Remote sensing

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