Mechanisms of Landslide Destabilization Induced by Glacier-Retreat on Tungnakvíslarjökull Area, Iceland

Pascal Lacroix (1) , Joaquin M. C. Belart , Etienne Berthier (2) , Dorsteinn Sæmundsson , Kristín. Jónsdóttir

1 ISTerre - Institut des Sciences de la Terre
2 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales

The massive worldwide deglaciation leads to more frequent slope instabilities in mountainous terrains. The physical processes leading to such destabilizations are poorly constrained due to little monitoring of dynamic parameters at the local scale. Here we study a very large slow-moving landslide (∼0.8 km²), on the flank of Tungnakvíslarjökull glacier in Iceland. Based on a combination of remote sensing images, we monitor the landslide and glacier kinematics over 75 years, with a focus over the period 1999-2019 when rapid glacier wastage has been observed. The landslide accelerates from 2 to 45 m/yr in the 6 years following a sudden increase in glacier mass loss. This acceleration coincides with intense quake activity (Mℓ < 2.8), recorded by a regional seismic network. We show that this seismicity is caused by the landslide sliding on a rough surface. The evolution of the quake magnitudes suggests a progressive segmentation of the landslide mass during its acceleration.

Keywords: landslide; glacier-retreat; remote-sensing; kinematics; seismology; asperity

Domains: Sciences of the Universe [physics]; Earth Sciences

Pascal Lacroix, Joaquin M. C. Belart, Etienne Berthier, Dorsteinn Sæmundsson, Kristín. Jónsdóttir. Mechanisms of Landslide Destabilization Induced by Glacier-Retreat on Tungnakvíslarjökull Area, Iceland. Geophysical Research Letters, 2022, 49, ⟨10.1029/2022GL098302⟩. ⟨insu-03861045⟩