Repeated failures of the giant Beshkiol Landslide and their impact on the long-term Naryn Basin floodings, Kyrgyz Tien Shan

Losen, J.; Rizza, M.; Nutz, A.; Henriquet, M.; Schuster, M.S.; Rakhmedinov, E.; Baikulov, S.; Abdrakhmatov, K.; Fleury, J.; Siame, L.

doi:10.1016/j.geomorph.2024.109121

Repeated failures of the giant Beshkiol Landslide and their impact on the long-term Naryn Basin floodings, Kyrgyz Tien Shan

Title

Repeated failures of the giant Beshkiol Landslide and their impact on the long-term Naryn Basin floodings, Kyrgyz Tien Shan

Author

Losen, J. (Aix Marseille Université)
Rizza, M. (Université du Québec à Montréal; Aix Marseille Université)
Nutz, A. (Aix Marseille Université)
Henriquet, M. (TU Delft Astrodynamics & Space Missions; Aix Marseille Université)
Schuster, M.S. (TU Delft Control & Simulation; Institut Terre et Environnement de Strasbourg (ITES))
Rakhmedinov, E. (National Academy of Sciences of the Kyrgyz Republic)
Baikulov, S. (National Academy of Sciences of the Kyrgyz Republic)
Abdrakhmatov, K. (National Academy of Sciences of the Kyrgyz Republic)
Fleury, J. (Aix Marseille Université)
Siame, L. (Aix Marseille Université)

Date

2024

Abstract

Landslides are major hazards that lead to cataclysmic changes in regional physiography. Their consequences are particularly significant when they affect a river system, forming dammed-lake upstream that represents a high flood threat for the downstream region. The Naryn River is the largest river in the Kyrgyz Tien Shan and is of great economic importance. The Beshkiol Landslide, the largest one in Central Asia but of unknown age, has most likely blocked the Naryn River in the past during the Late Pleistocene, with evidence of thick lacustrine deposits as well as numerous paleo-shorelines preserved upstream. In this study, a detailed geomorphological and sedimentological analysis combined with luminescence and ¹⁴C dating provides a strong chronological framework to refine the dynamics between the Beshkiol landslides and dammed-lakes in the Naryn Basin. We propose that the Beshkiol Landslide was first triggered 51.9 ± 4.4 kyrs ago, with a 410 m-high dam that blocked the Naryn River. A first lake with a total volume of 121 ± 50 km³ lasted for >37.0 ± 5.1 kyrs, one of the longest landslide-dammed lake residence time ever documented in the world. Our sedimentological observations highlight a catastrophic lake outburst flood between 15.6 and 14.1 kyrs cal BP, likely related to a landslide dam breach. A short-lived phase of fluvial erosion impacted the whole Naryn Basin followed by a second landslide activation (280 m- high dam) and subsequent flooding by a second lake of 27 ± 10 km³. This second lake had a minimum residence time of 7.7 ± 1.3 kyrs before its final gradual drainage that was followed by a fluvial erosional phase still active today in the Naryn Basin. We also suggest that the distal unconsolidated part of the Beshkiol Landslide could be remobilized in the event of an earthquake and/or extreme rain episode, causing a potentially dam of the Naryn River, which would have strong regional economic impacts.

Subject

Dammed-lake
Kyrgyzstan
Landslide
Quaternary dating

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DOI

https://doi.org/10.1016/j.geomorph.2024.109121

Embargo date

2024-09-09

ISSN

0169-555X

Source

Geomorphology, 453

Bibliographical note

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Part of collection

Institutional Repository

Document type

journal article

Rights

Files

file embargo until 2024-09-09