Active landslides in the Rogun Catchment, Tajikistan, and their river damming hazard potential

Abstract

The region of Tajikistan where the Rogun Hydropower Project is currently under construction has experienced large and catastrophic slope failures in the past, often triggered by earthquakes. Co-seismic slope failures are thus common and pose a high hazard potential; however, to date, no specific analysis of slope activity in this area has been presented in international journals. Here, we present an inventory of active landslides identified through satellite imagery analysis and in particular by exploiting space-borne differential radar interferometry. Surface displacements provide the basis for the detection of active slope instabilities, which are then further classified by using geomorphological indicators visible in optical satellite imagery. Additionally, the proximity of active landslides to tectonic lineaments, as well as regional seismicity, is analysed to investigate potential relationships and to provide an integrated river damming hazard potential. The results show that approximately 31% of all detected landslides would have a high damming hazard potential upon catastrophic failure, highlighting the importance of such phenomena for efficient long-term land use planning and management of hydropower plants.

Response of a large deep-seated gravitational slope deformation to meteorological, seismic, and deglaciation drivers as measured by InSAR

“…However, domain boundaries do not correlate with any prominent or obvious geomorphic feature, potentially indicating a subdivision of the landslide body into discrete blocks. Possible reasons may include i) the recent activation of the slope-scale instability, resulting in an incipient separation of landslide blocks that is not yet reflected in the formation of surface features, or ii) a spatially different deformation response to different drivers, reflecting a "slope deformation complex", without the presence of kinematically constrained blocks that move fully independently of one another (see also Jones et al, 2021).…”

Sediment Sources, Erosion Processes, and Interactions with Climate Dynamics in the Vakhsh River Basin, Tajikistan

“…The only other large earthquake in the basin during the past century was the 1949 Khait earthquake (M = 7.6), located about 50 km northeast of Gharm [58]. Although recent seismic activity in the basin appears to mostly initiate small landslides and rockfall along unstable cutslopes, contemporary seismicity has been implicated in the activation of large, slow-moving landslides and rock failures as noted [56]. Small earthquakes could also disrupt steep, rocky slopes, making them more susceptible to future failure.…”

“…Climate-related reactivation of ancient landslides may also contribute huge, spatially discrete volumes of sediment to the Vakhsh River. Recent remote-sensing evidence suggests an association between seismic activity in the basin and the activation of large, slow-moving slope failures [56].…”

Central Asia Rockslides Inventory: Compilation, Analysis and Training—Progress of the IPL WCoE

“…The Central Asian rockslide database serves as a reference point for various regional and site-specific studies of natural hazards and risks associated with rockslides, rock avalanches and rockslide dams (e.g. Fomenko et al 2020;Jones et al 2021). It has been also used for the landslide susceptibility assessment of the Central Asian states performed within the frames of the ongoing World Bank funded project.…”