Thursday, April 19, 2018, 16:00
WHGA Auditorium
Fritz Schlunegger, Institute of Geological Sciences, University of Bern
Abstract:
I present the experimental design and the first results of an interdisciplinary project between the fields of
Earth Sciences (geology and geomorphology) and Physics (particle physics methodologies) where we aim at imaging
the base of an Alpine glacier with nuclear emulsion particle detectors exposed to the cosmic muon flux. To this
extent, we have installed emulsion films at three sites along the tunnel of the Jungfraubahn tunnel and mapped
the shape of the bedrock underneath the Alteschglacier on the southern side. We used the patterns of detected muons
to map the orientation of the bedrock underneath this glacier. We were able to show that the dip and strike angles
of the reconstructed bedrock surface agree with those of the hillslope exposed above the glacier. In addition, the
orientation of the bedrock is parallel to the glacier's flow direction estimated from the topography of the glacier
surface. These morphometric data indicate that the ice, at least within 50 m depth below the surface, has passively
slid on the preexisting hillslope. However, because of the steep dip of the bedrock-ice interface, a further lowering
of the ice surface in response to ongoing warming will strongly increase the risk for bedrock failure in the area
surrounding the research station.
Related reference:
R. Nishiyama, A. Ariga, T. Ariga, S. Käser, A. Lechmann,
D. Mair, P. Scampoli, M. Vladymyrov, A. Ereditato, F. Schlunegger
First measurement of ice-bedrock interface of alpine glaciers by cosmic muon radiography.
Geophysical Research Letters, 44, 6244-6251. 2017. DOI: 10.1002/2017GL073599