Suchergebnisse

Abstract. Landslides are major hazards that may pose serious
threats to mountain communities. Even landslides in remote mountains could
have non-negligible impacts on populous regions by blocking large rivers and
forming dam-breached mega floods. Usually, there are slope deformations
before major landslides occur, and detecting precursors such as slope
movement before major landslides is important for preventing possible
disasters. In this work, we applied multi-temporal optical remote sensing
images (Landsat 7 and Sentinel-2) and an image correlation method to detect
subpixel slope deformations of a slope near the town of Mindu in the Tibet
Autonomous Region. This slope is located on the right bank of the Jinsha
River, ∼80 km downstream from the famous Baige landslide. We used a
DEM-derived aspect to restrain background noise in image correlation
results. We found the slope remained stable from November 2015 to November
2018 and moved significantly from November 2018. We used more data to
analyse slope movement in 2019 and found retrogressive slope movements with
increasingly large deformations near the riverbank. We also analysed
spatial–temporal patterns of the slope deformation from October 2018 to
February 2020 and found seasonal variations in slope deformations. Only the
foot of the slope moved in dry seasons, whereas the entire slope was activated
in rainy seasons. Until 24 August 2019, the size of the slope with
displacements larger than 3 m was similar to that of the Baige landslide.
However, the river width at the foot of this slope is much narrower than the
river width at the foot of the Baige landslide. We speculate it may continue
to slide down and threaten the Jinsha River. Further modelling works should
be carried out to check if the imminent landslide could dam the Jinsha River and
measures should be taken to mitigate possible dam breach flood disasters. This
work illustrates the potential of using optical remote sensing to monitor
slope deformations over remote mountain regions.