Reflexionsseismische Datenanalyse des Russell-Gletschers, Grönland = Reflection Seismic Data Analysis of Russell Glacier, Greenland
Modelling the glacier dynamics of the Greenland Ice Sheet is a central part of climate research. To be able to model the processes that influence a glacier’s flow, the position of its ice-bed contact is a basal boundary condition. Using five different P-wave reflection seismic datasets, the subsurfa...
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| Format: | Bachelor Thesis |
| Language: | English |
| Published: |
2016
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| Online Access: | https://publikationen.bibliothek.kit.edu/1000063865 https://publikationen.bibliothek.kit.edu/1000063865/3975922 https://doi.org/10.5445/IR/1000063865 http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:swb:90-638650 |
| Summary: | Modelling the glacier dynamics of the Greenland Ice Sheet is a central part of climate research. To be able to model the processes that influence a glacier’s flow, the position of its ice-bed contact is a basal boundary condition. Using five different P-wave reflection seismic datasets, the subsurface structure of Russell Glacier, which is a land-terminating glacier in southwest Greenland, is inves- tigated. The data have been recorded by the glaciology group of the Alfred-Wegener Institute, in the ablation zone of Russell Glacier. To investigate the efficiency of the minivibrator source ELVIS III on polar glaciers having ice thicknesses up to several kilometers, a dataset using the ELVIS source is compared to an equivalent explosive seismic dataset. The question to answer is, if the approximately 600 m deep glacier bed and additional subglacial structures are displayed by the vibroseis data. As the maximally 10-fold vibroseis data, in contrast to the maximally 2-fold ex- plosive seismic data, don’t reveal any reflection signals, it is concluded that the penetration depth of the ELVIS signal is too small to resolve subglacial structures on polar glaciers. The subsurface structure of the survey area is investigated with the help of two explosive seismic datasets. In the resulting depth profiles lying perpendicular to each other, a distinct topography of the glacier bed as well as a stratification of the subglacial material is visible. The propagation velocities of seismic P-waves in the subsurface layers are firstly determined by applying Dix’ method at two additional explosive datasets. As the subglacial material couldn’t be determined that way, for the reason that the ap- purtenant velocity value determined with Dix’ method are not reliable due to the topography of the covered reflector, the polarity of the reflection coefficient associ- ated with the first layer boundary are reconstructed using the material classification from Christianson et al. (2014). For future applications of Dix’ method in order to ... |
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