1999/01/01 by G. Hilmar Gudmundsson, Andreas Bauder, Martin Lüthi +3
Earth and Planetary Sciences · Environmental Science · #Climate change and permafrost #Cryospheric studies and observations #Landslides and related hazards
paper · pdf · doi:10.3189/172756499781821751
openalex publication_date 1999/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Abstract Over a two-year period, continuous measurements of temporal changes in tilt, conducted with a string of tilt meters in a borehole on Unteraargletscher, Bernese Alps, Switzerland, have been used to estimate the basal-motion component. This estimation is based on a comparison of the measurements with synthetic tilt curves, computed using a parameterization of a simplified flow field. The best agreement is found for a ratio of basal motion to forward motion due to ice deformation (slip ratio) equal to about 1.2. Measured tilt curves exhibit a number of different transient features. While an overall increase in tilt angle is observed at every tilt-meter location, two of the sensors recorded anomalous tilt behaviour. These anomalies are characterized by sudden and drastic variations in tilt. A particularly intriguing example of such short-term tilt variations was recorded with a tilt meter positioned 40 m above the bed during the 1997 summer melt season.