Articles | Volume 11, issue 6
The Cryosphere, 11, 2957–2974, 2017

Special issue: The evolution of permafrost in mountain regions

The Cryosphere, 11, 2957–2974, 2017

Research article 14 Dec 2017

Research article | 14 Dec 2017

Resolution capacity of geophysical monitoring regarding permafrost degradation induced by hydrological processes

Benjamin Mewes1, Christin Hilbich2, Reynald Delaloye2, and Christian Hauck2 Benjamin Mewes et al.
  • 1Institute of Hydrology, Water Resources Management and Environmental Engineering, Ruhr-University Bochum, Bochum, 44801, Germany
  • 2Department of Geosciences, University of Fribourg, Fribourg, 1700, Switzerland

Abstract. Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.