Interferometric Stacking toward Geohazard Identification and Geotechnical Asset Monitoring

Geotechnical assets are those found along transportation environments and are made up of or supported by earth materials. A geotechnical asset management program aims to achieve life-cycle performance goals by maintaining the geotechnical assets in a safe, cost-effective, and timely manner. Interferometric synthetic aperture radar, a remote sensing technique that derives ground deformation information from satellite-based radar data, is proposed as a monitoring method in the context of geotechnical asset management. A total of 90 ERS-1, ERS-2, and ENVISAT radar images, acquired from 1992 through 2010, are processed using two interferometric stacking techniques to measure ground deformation along a railroad corridor. A local-scale study was first conducted over a known slide (S-1) where total displacements up to 6 cm were measured. Then a regional-scale study was performed to locate hazard zones. Six potential geo-hazard zones were identified along the railroad corridor based on five criteria: slope distance, slope height, slope angle, average downslope velocity, and total downslope displacement. Interferometric stacking is shown to be quite useful for geotechnical asset management, as this remote sensing technique allows for an indirect method of quantifying asset condition and allows for the long-term monitoring of geotechnical assets that a management program aims to achieve.