Transportation Corridor

3vG conducted a historical analysis and processed data on a transportation corridor along the Thompson River near Ashcroft, British Columbia. This 10-kilometer stretch has numerous slope instabilities that threaten a major highway and two railways.

Challenge

• At least 14 significant historical landslides
• Additional hazards exist outside this 10km stretch
• Ongoing monitoring of known slides using ground-based techniques is costly and spatially limited
• Identifying new instabilities and prioritizing existing hazards over a large area
• Past slide acceleration events have disabled sections of the railway
• Ongoing slow displacement and future accelerated slides threaten to block the transportation corridor

Solution & Results

3v Geomatics analyzed 38 RADARSAT-2 images acquired between January 2009 and October 2013. Focusing on a zone 18 km wide by 52 km long, displacement was identified in 18 distinct areas. The fastest displacement measured was over 16 cm/year, while the slowest was less than 1 cm/year. The high sensitivity of InSAR measurements facilitated the identification of unknown displacement, as well as locating the extent of known displacement areas. The results were presented as a rate map and as thousands of time series graphs showing displacement histories for points within the displacement areas.

Displacement over a section of the valley, colour coded to +/- 3cm/year is shown on the left. The right image shows a displacement time series graph for a measurement point within a slow landslide.

Benefits

• High measurement density and large geographic coverage per image
• Scalable for larger networks of transportation corridors
• Ability to identify the extents of all displacement areas
• Provides advanced reconnaissance to discover and prioritize locations of displacement for in-situ scrutiny
• Facilitates a more complete understanding of complex landscapes with multiple active and historical geohazards
• Insight into past displacement trends to mitigate current and future risks

Conclusion

3vG provides cost-effective and efficient solutions for both historical analysis and ongoing monitoring of geohazards that threaten transportation infrastructure. Our monitoring services can be used as a standalone monitoring system or to complement in-situ instrumentation. InSAR’s wide coverage, density, scalability, sensitivity, and archive availability is a preemptive measure against geohazards over vast regions.

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