Who needs resolution anyway? Three satellite InSAR case studies comparing coincident and contemporary datasets

Authors: Holden, D; Cerin, D; Mäkitaavola, K; Ersholm, F; Sjöberg, J Download Paper

DOI https://doi.org/10.36487/ACG_repo/2135_12

Cite As:
Holden, D, Cerin, D, Mäkitaavola, K, Ersholm, F & Sjöberg, J 2021, 'Who needs resolution anyway? Three satellite InSAR case studies comparing coincident and contemporary datasets', in PM Dight (ed.), SSIM 2021: Second International Slope Stability in Mining, Australian Centre for Geomechanics, Perth, pp. 211-226, https://doi.org/10.36487/ACG_repo/2135_12



Abstract:
Satellite interferometric synthetic aperture radar (InSAR) is a powerful and economical tool for monitoring ground movement, which benefits from wide coverage, high sensitivity to displacement, and high spatial measurement density, with no need for site access. Currently, there are several options for satellite synthetic aperture radar (SAR) imagery available and numerous missions will be launching over the next few years. A number of satellite parameters have a direct impact on the cost and effectiveness of monitoring programs. This paper presents four case studies that each include results over slope instabilities from multiple contemporary InSAR datasets including data from the TerraSAR-X (TSX), Sentinel-1 (S1), and ALOS-2 satellite constellations. The case study locations include two mines in northern Sweden, Kiruna and Malmberget, and two other sites in the USA; a mine in Nevada and a natural slope in North Dakota. For each of these case studies, the impact of the image resolution on the detection and detail of the displacement areas is compared. While the comparisons focus on the resolution differences, other factors such as the satellite line of sight (LOS), revisit period, sensitivity to displacement, and data cost are also discussed. The two US mine case studies show how TSX data captures higher displacement magnitudes than S1, although the InSAR displacement measurement capabilities of TSX (11 day revisits) are also exceeded. The North Dakota example shows how lower resolution S1 data is unable to detect a smaller but potentially consequential displacement area while 3 m ALOS-2 results do. The examples in Sweden illustrate the higher level of displacement detail in ALOS-2 results compared to S1 results. Some general InSAR monitoring guidelines are also presented relating the surface area of the deforming area to recommended SAR satellite monitoring parameters.

Keywords: InSAR monitoring risk mitigation resolution

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