ALOS/PALSAR InSAR Time-Series Analysis for Detecting Very Slow-Moving Landslides in Southern Kyrgyzstan

Abstract

This study focuses on evaluating the potential of ALOS/PALSAR time-series data to analyze the activation of deep-seated landslides in the foothill zone of the high mountain Alai range in the southern Tien Shan (Kyrgyzstan). Most previous field-based landslide investigations have revealed that many landslides have indicators for ongoing slow movements in the form of migrating and newly developing cracks. L-band ALOS/PALSAR data for the period between 2007 and 2010 are available for the 484 km 2 area in this study. We analyzed these data using the Small Baseline Subset (SBAS) time-series technique to assess the surface deformation related to the activation of landslides. We observed up to ±17 mm/year of LOS velocity deformation rates, which were projected along the local steepest slope and resulted in velocity rates of up to −63 mm/year. The obtained rates indicate very slow movement of the deep-seated landslides during the observation time. We also compared these movements with precipitation and earthquake records. The results suggest that the deformation peaks correlate with rainfall in the 3 preceding months and with an earthquake event. Overall, the results of this study indicated the great potential of L-band InSAR time series analysis for OPEN ACCESS Remote Sens. 2015, 7 8974 efficient spatiotemporal identification and monitoring of slope activations in this region of high landslide activity in Southern Kyrgyzstan.

Deep‐seated gravitational slope deformation (DSGSD) and slow‐moving landslides in the southern Tien Shan Mountains: new insights from InSAR, tectonic and geomorphic analysis

“…We searched for a possible correlation between the patterns that were observed in the displacement time series and precipitation. Our 4‐year observation period did not reveal a direct relationship between the rate of slope movement and precipitation (Teshebaeva et al ., ). Nevertheless, in future studies decadal InSAR time series may help to elucidate such potential relationships.…”

“…To the south, the Paleozoic basement of the Alai Range forms the substratum of the intra-mountain Alai Valley, which is located immediately north of the north-vergent thrust belt of the Pamir (Trans Alai)-Tien Shan collision zone between the northwestern Indian indenter and Eurasia (Burtman and Molnar, 1993). The south-dipping, range-bounding faults of the Alai Range have been active tectonically since the Oligocene (Coutand et al, 2002;Sobel et al, 2011), and they are considered to be an integral part of the Pamir orogenic wedge (Burtman, 2006;Teshebaeva et al, 2014). The present-day convergence rate between India and Eurasia using spacegeodetic measurements is approximately 25 mm year À1 (Reigber et al, 2001;Zubovich et al, 2010).…”

“…The toe areas of hummocky slopes along range fronts have apparently displaced the fluvial network, which suggests an efficient, perhaps protracted and sustained, mechanism of mass transfer from the hillslopes to the fluvial channel systems. These features altogether make this region a good setting to decode the roles of different forcing mechanisms on mass movements and their temporal behaviour (Chediya, ; Wetzel et al ., ; Abdrakhmatov et al ., ; Teshebaeva et al ., ). We hypothesize that the active tectonics and uplift in the Tien Shan are the main forcing mechanisms to sustain the necessary gravitational forces of slope deformation and form DSGSD along the Alai Range.…”

“…The flanks of the Alai Range in this region record numerous voluminous landslides each year that have affected the morphology of range fronts and their piedmont regions (Roessner et al ., ; Strom and Korup, ; Danneels et al ., ; Havenith et al ., ). Deep‐reaching and slow‐moving mass movements are ubiquitous phenomena in intermountain valleys and along fault‐controlled mountain fronts in the Alai Range of the Tien Shan (Wetzel et al ., ; Havenith et al ., ; Teshebaeva et al ., ). Typically, range fronts exhibit multiple cuspate break‐off scarps, extensional, slope‐parallel trenches and evidence of rotational movements.…”

Wide-Area Landslide Deformation Mapping with Multi-Path ALOS PALSAR Data Stacks: A Case Study of Three Gorges Area, China

“…Since then it has been frequently applied in displacement monitoring in rural areas [11,[19][20][21][22]. Compared with the original method which can operate with separated subsets of SAR acquisitions, isolated interferograms are not allowed in StaMPS SBAS analysis.…”