Joint approach using satellite techniques for slope instability detection and monitoring

Abstract

A joint approach using satellite techniques was applied to two different regions (Sellas and Chalkeio villages) of Peloponissos (Greece) in order to detect and monitor slope instability. In the context of the research effort, a GPS campaign network, along with one permanent GPS station and a corner reflector (CR) network, was established at each region. From the two GPS campaigns that were carried out, ground displacements in the north and east components for Sellas region reached a magnitude of 9 and 8 mm, respectively, whereas for Chalkeio they were of the order of 1 cm and 8 mm, respectively. These results, however, are still preliminary and need validation from additional GPS campaigns that are planned to be carried out in future. The temporal resolution provided by the position time series of the permanent GPS stations highlighted the main features of both instability phenomena, that is, sensitivity at both horizontal components of motion for the Sellas region and slow linear trends for the Chalkeio region. The achieved precision of the daily solutions for both permanent GPS stations was found to be 1–3 mm for the horizontal components and 5–8 mm for the vertical components. Regarding the preliminary study of differential synthetic aperture radar (SAR) interferometry (DInSAR) in CR network, each reflector has been identified in SAR imagery, but at present the volume of SAR acquisitions is not adequate for providing safe deformation and error estimations. On the other hand, the permanent scatterers interferometry and small baselines subset (SBAS) techniques revealed a discontinuity in retrospective deformation rate along the observed rupture of Chalkeio village of almost 6 mm year⁻¹.

Acknowledgements

We thank ESA and CSA for SAR data from ASAR/ENVISAT (ESA Category-1 Project 7936) and RADARSAT-2 (SOAR-EU Project 6751). We also thank Ktimatologio S.A. for the orthophoto imagery. The purchase of the two GPS stations, the CRs and the campaigns that were carried out were supported in the frame of the Project ‘System Development on monitoring slope stability for the prevention of Landslides and Training of Local Public Authorities in the region of Peloponisos’ (EL0071-EEA grants, EEA Financial Mechanism/the Norwegian Financial Mechanism). Finally, we thank Dr A. Ganas for his contribution to the preparation of the project and his work at its early stages.