SAR INTERFEROMETRY FOR SURFACE AND INFRASTRUCTURE
MOVEMENT MONITORING IN MINING ENVIRONMENT
ABSTRACT
Over the past ten years, Synthetic Aperture Radar Interferometry (InSAR) has been widely used in ground
surface deformation monitoring (e.g. ground subsidence, earthquake, volcanic field monitoring, etc.). With
this technique, changes in phase between two SAR acquisitions (called interferometric phase) are used to
detect centimeter to millimeter surface displacements over a large area and with high spatial resolution.
InSAR can be used as a tool to assist the siting and design of new infrastructure as well as highlighting the
risk to existing structures in areas of unstable terrain.
This paper presents the results of a project carried out by Effigis which made use of SAR interferometry in
the context of monitoring terrain and infrastructure stability in a northern mining environment that is
affected by permafrost seasonal and long term changes.
TerraSAR-X images acquired during two periods, August to November 2012 and March to October 2013,
were used to measure the deformations and/or movement of ground surface, infrastructure and stockpiles
caused by seasonal changes in permafrost extent in a mining environment located in Nunavik, Quebec. The
results (Figure 1) show that spatial and temporal distributions of surface displacements are in accordance
with ground truth measurements. More important displacements were observed in loose soil areas while, as
expected, none were detected in bedrock and rock outcrop areas. The areas most affected by active layer
changes showed negative surface displacement in the thaw settlement period and positive surface
displacement in the frost heave period.
This study confirms that SAR interferometry has great potential for operational applications related to risks
induced by surface deformation or movement in mining environments. It shows that this technique can be
used to produce reliable maps of surface deformation and/or movement and monitor the vertical
displacement of important infrastructure.
Figure 1 – Map of surface displacements in a mining environment (Nunavik, Quebec) affected by
permafrost changes in thawing season (summer) of 2012
KEYWORDS
SAR interferometry, TerraSAR-X, surface deformation, infrastructure stability, permafrost