Monitoring the Recent Activity of Landslides in the Mailuu-Suu Valley (Kyrgyzstan) Using Radar and Optical Remote Sensing Techniques

Abstract

Central Asian mountain regions are prone to multiple types of natural hazards, often causing damage due to the impact of mass movements. In spring 2017, Kyrgyzstan suffered significant losses from a massive landslide activation event, during which also two of the largest deep-seated mass movements of the former mining area of Mailuu-Suu—the Koytash and Tektonik landslides—were reactivated. This study consists of the use of optical and radar satellite data to highlight deformation zones and identify displacements prior to the collapse of Koytash and to the more superficial deformation on Tektonik. Especially for the first one, the comparison of Digital Elevation Models of 2011 and 2017 (respectively, satellite and unmanned aerial vehicle (UAV) imagery-based) highlights areas of depletion and accumulation, in the scarp and near the toe, respectively. The Differential Synthetic Aperture Radar Interferometry analysis identified slow displacements during the months preceding the reactivation in April 2017, indicating the long-term sliding activity of Koytash and Tektonik. This was confirmed by the computation of deformation time series, showing a positive velocity anomaly on the upper part of both landslides. Furthermore, the analysis of the Normalized Difference Vegetation Index revealed land cover changes associated with the sliding process between June 2016 and October 2017. In addition, in situ data from a local meteorological station highlighted the important contribution of precipitation as a trigger of the collapse. The multidirectional approach used in this study demonstrated the efficiency of applying multiple remote sensing techniques, combined with a meteorological analysis, to identify triggering factors and monitor the activity of landslides.

Landslide-Induced Mass Transport of Radionuclides along Transboundary Mailuu-Suu River Networks in Central Asia

“…[3]. Mailuu-Suu is a former uranium mining area [9,45]. In and around the town, uranium mining and milling activities started in 1946 and lasted until 1968.…”

“…Among the most troublesome are landslides, which occur on mountain slopes and in narrow canyons [2,6,8]. In the Kyrgyz part of the Fergana basin, the first recorded massive activation of landslides occurred in 1954 and was followed by other events in 1958, 1969, 1979, 1988, 1993-1994, 1998, 2003-2005, and 2017 [2,9]. The typical landslide is a translational slide in this region.…”

“…These new questions will be answered in the current study. The study area, the Mailuu-Suu catchment across Kyrgyzstan and Uzbekistan, is a landslide prone area ( Figure 1) [2,6,9]. This area is frequently affected by seismic activities (e.g., earthquake), which is an important trigger of landslides [6].…”

Influence of Earthquakes on Landslide Susceptibility in a Seismic Prone Catchment in Central Asia

“…One hotspot of earthquakes and landslides in the Tien Shan area is the Ferghana Valley, where the studied Mailuu-Suu catchment (Figure 1c) is located [50,51]. In the Kyrgyz part of the Ferghana Valley, the first recorded massive activation of landslides occurred in 1954 and was followed by other events in 1958, 1969, 1979, 1988, 1993-1994, 1998, 2003-2005, and 2017 [50,52]. The studied Mailuu-Suu catchment (Figure 1) and its neighbouring areas are also frequently affected by earthquakes [48,50].…”

The Detection of Active Sinkholes by Airborne Differential LiDAR DEMs and InSAR Cloud Computing Tools

“…, De Luca et al[74], Galve et al[75], Manunta et al[76], Piroton et al[77] and the GEP website (https://geohazards-tep.eu/#! (accessed on 16 June 2021)).…”