Large rock-slope failures impacting lakes

As a sedimentologist with a major in climate geology I am especially interested in natural hazards in mountaineous regions. In my research I focus on rock-slope failures that have impacted (paleo-) lakes.

Why study rock-slope failures in combination with lakes?

1. Massive rock-slope failures impacting lakes have a high hazard potential. They are linked to phenomena like impact waves and highly fluidized rock material. Lubrication due to the entrainment of water and fine sediments is hypothesized to play a major role for rock avalanches to go very far.

2. Climate change forces us to face a drastic change of the high-mountaineous landscape. Permafrost degradation and glacier retreat will lead to more destabilized mountain flanks being exposed above newly built (meltwater-) lakes. This leads to a complex disaster-chain effect with an increasing risk of outburst floods triggered by impacting rock material.

3. The sediment archives of lakes can provide us with information on the characteristics of rock-slope failures that impacted the lake. The lakes act as natural chronometers.

Research focus

Magnitude and frequency of rock-slope failures

Magnitude and frequency of rock-slope failures are often misestimated because single event deposits are camouflaged on land. Rock-slope failure deposits revealed in lake sediments can be deciphered in time and space. This approach makes it possible to decipher multistage rock-slope failures from one single mountain flank.

• Lake Oeschinen (Bernese Oberland, Switzerland).
  • multistage rock-slope failures in a seismically active Alpine region
  • impact on a lake: impact wave and energy transfer
• Lake Eibsee / Zugspitze rock avalanche (Bavaria, Germany).
  • event phases of a rock avalanche

Mobility and entrainment processes in rock avalanches

Rock avalanches show a complex flow behavior in terms of entrainment and runout length. The character of the entrained material and the terrain significantly contribute to the velocity and runout length of the rock avalanche. I am interested in a better understanding of how entrainment works and how entrainment influences the mobility of a rock avalanche, especially after the impact on a lake.

• Lake Eibsee / Zugspitze rock avalanche (Bavaria, Germany).
  • evidence of paleolake, lubrication
• Lake Bonaduz / Flims rock avalanche (Grisons, Switzerland).
  • generation and mobility of flood deposits, characteristics of the Toma hills
• Tschirgant rock avalanche (Oetz valley, Austria).
  • entrainment processes