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Dynamics of a Giant Slow Landslide Along the Coast of the Aral Sea, Central Asia
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  • Gokhan ASLAN,
  • Marcello de Michele,
  • Daniel Raucoules,
  • François Renard,
  • Ziyadin Çakir
Gokhan ASLAN
BRGM

Corresponding Author:gokhanaslan3@gmail.com

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Marcello de Michele
BRGM
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Daniel Raucoules
BRGM Service géologique national
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François Renard
University of Oslo
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Ziyadin Çakir
Istanbul Technical University
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Abstract

We report here a slow-moving landslide revealed by Sentinel-1 interferometric time-series analysis. Located along the western coast of the Aral Sea, with a >80-km length and 4-km width, this is the world’s largest active landslide complex reported so far with a constant velocity of 40 mm/yr. Systematic subsidence up to 5 mm/yr, is also observed along narrow strips of terraces that appear to result from rotations of fault-bounded blocks. The horizontal deformation does not correlate with the annual variations of the water level in the Aral Sea over the same period, indicating a long-term forcing of this landslide that might be caused by the long-term sea-level drop. The lateral spreadings involve the competent limestone beds lying horizontally on plastic clay- and evaporite-rich layers. We propose a conceptual model for the mechanism of landslides that appear to be controlled by the attitude of bedding, lithological sequence, hydrogeology, and low angle faults.