Suitability Assessment of X-Band Satellite SAR Data for Geotechnical Monitoring of Site Scale Slow Moving Landslides

Guadalupe Bru,Rubén Iglesias,Eugenio Sansosti,Tamara Abajo,Antonio Morales,José Fernández,Jordi Mallorqui,Joaquin Escayo

doi:10.3390/rs10060936

Abstract

This work addresses the suitability of using X-band Synthetic Aperture Radar (SAR) data for operational geotechnical monitoring of site scale slow moving landslides, affecting urban areas and infrastructures. The scale of these studies requires high resolution data. We propose a procedure for the practical use of SAR data in geotechnical landslides campaigns, that includes an appropriate dataset selection taking into account the scenario characteristics, a visibility analysis, and considerations when comparing advanced differential SAR interferometry (A-DInSAR) results with other monitoring techniques. We have determined that Sentinel-2 satellite optical images are suited for performing high resolution land cover classifications, which results in the achievement of qualitative visibility maps. We also concluded that A-DInSAR is a very powerful and versatile tool for detailed scale landslide monitoring, although in combination with other instrumentation techniques.

Highlights

Landslides are a globally widespread major natural hazard [1,2] that can take place at various temporal and spatial scales
We propose a procedure for the practical use of Synthetic Aperture Radar (SAR) data in geotechnical landslides campaigns, that includes an appropriate dataset selection taking into account the scenario characteristics, a visibility analysis, and considerations when comparing advanced differential SAR interferometry (A-DInSAR) results with other monitoring techniques
We have determined that Sentinel-2 satellite optical images are suited for performing high resolution land cover classifications, which results in the achievement of qualitative visibility maps

Summary

Introduction

Landslides are a globally widespread major natural hazard [1,2] that can take place at various temporal and spatial scales. In situ observation techniques have several limitations: (a) the setting of sparse observation points, which usually cover small areas, giving an limited overview of the landslide extent and of the spatial distribution of the displacement field; (b) observations are constrained to accessible areas; (c) instrumentation is usually placed where activity is expected (preventing any opportunity to obtain information on sudden or unknown active areas); (d) reference stations might not be stable, in particular when only small areas are covered with the observation system; (e) displacement information is only available after the first survey is performed, so that there is usually a lack of information about previous epochs that could help us to understand and characterize mass movements; and (f) involvement of staff in field campaigns, direct data collection, and maintenance of continuous recording systems, can be very expensive for the institutions involved in the monitoring. All these considerations affect the sustainability of such a monitoring system, which is a limiting aspect for the availability of long-term studies of unstable slopes [5]

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