Landslide Investigation Using Differential Synthetic Aperture Radar Interferometry: A Case Study of Balloran Dam Area in Syria

Abstract

<p><strong>Abstract.</strong> Landslides are one of the main geological hazards that can cause critical damage to the infrastructure in an area and can result in serious risks to the people’s safety there. Landslides can be investigated and monitored using field survey, aerial mapping and high resolution optical satellite data analysis. However, these methods are relatively time-consuming. Interferometric synthetic aperture radar (InSAR) can investigate and monitor landslides and provide sub-centimetre accuracy for ground-surface deformation when time series analysis techniques are employed. In this research, differential synthetic aperture radar interferometry was applied on Sentinel-1 data of two Single Look Complex (SLC) images from 16 October 2018 and 21 March 2019 in the Interferometric Wide (IW) swath mode using the Sentinel application platform (SNAP) to determine the extreme ground-surface deformations, as a prelude to landslides occurrence in Balloran dam area in the north-west of Syria, where the ophiolite complex deposits of the Maastrichtian are exposed causing, due to the heavy rains, several landslides affecting the road network in this area every year. The results reveal ground-surface deformations during the study period along the satellite line of sight near to the main road in Balloran dam area with a maximum value reaches to around 20 cm. The D-InSAR results were compared to the D-GPS results of 10 validation points along the main road in the study area, where the RMS difference value was 20 cm.</p>

Integration of Gis and Advanced Remote Sensing Techniques for Landslide Hazard Assessment: A Case Study of Northwest Syria

“…Road networks in the study area are susceptible to be damaged annually due to unforeseen landslides after intense rainfall events. These unforeseen landslides threaten the lives and the properties of people who live there (Hammad et al, 2019).…”

“…Landslide hazard investigation, assessment, monitoring and mapping processes become increasingly important in most mountainous and hilly regions around the world where landslides are a major hazard (kervyn et al, 2015) and (Hammad et al, 2019). So, landslide studies in those places are important to evaluate the relative contributions of all elements and factors involved in landslide process within an area and to identify the possible locations that might be affected by landslides in order to reduce risk on people in those areas and help local authorities in the process of future regional planning.…”

Landslide hazard assessment using advanced remote sensing techniques and GIS

“…The maximum value of the ground-surface deformation was at the validation point P3 with a deformation value of 75 cm in the southeast direction. However, the ground-surface deformation values of the other validation points were between 2 and 5 cm (Hammad et al, 2019).…”

“…Figure 5.40: Ground-surface deformation direction and magnitude values using D-GPS field measurements from 10 validation points in the Balloran Dam area during the study period. The star indicates the location of the landslide that occurred in March 2019 (Hammad et al, 2019).…”

“…By unwrapping the displacement phase using a software package called the Statistical-cost, Network-flow Algorithm for Phase Unwrapping (SNAPHU), it is possible to compute the unwrapped phase and sum the number of InSAR fringes to get the relative values of all related ground-surface deformations (Massonnet and Feigl, 1998;Rosen et al, 2000). Several researchers have indicated the usefulness of D-InSAR in landslide studies (Fruneau et al, 1996;Singhroy et al, 1998;Rott et al, 1999;Ye et al, 2004;Strozzi et al, 2005;Catani et al, 2005;Putri et al, 2013;Hammad et al, 2019).…”