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.