Using Interferometric Synthetic Aperture Radar (InSAR) to Detect Ground Movement Affection Roads

presented by John Kreft, Principal Geohazards Specialist & Digital Lead, WSP

12 March 2026

Road networks in regions such as Northland are increasingly exposed to moving landslides that can remain undetected until damage becomes operationally or economically significant. Traditional inspection and point-based monitoring methods often struggle to identify early-stage movement across long, remote corridors.

This presentation draws on recent InSAR analysis undertaken across the Northland state highway network, demonstrating how satellite-based ground movement data can be used to detect millimetre scale deformation beneath and adjacent to roads. The work highlights how InSAR can identify previously unrecognised slow landslides, provide historical movement trends, and support network scale prioritisation of geotechnical risk.

The presentation will discuss practical lessons from applying InSAR in heavily-vegetated, geologically-complex terrain, how the data can be integrated with field observations and asset management systems, and the potential role of InSAR as an early warning and decision-support tool for road controlling authorities.

Link to cloud recording Passcode: 6isp7Y#$