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Université de Fribourg

A monitoring system for spatiotemporal electrical self-potential measurements in cryospheric environments

Weigand, Maximilian ; Wagner, Florian M. ; Limbrock, Jonas K. ; Hilbich, Christin ; Hauck, Christian ; Kemna, Andreas

In: Geoscientific Instrumentation, Methods and Data Systems, 2020, vol. 9, no. 2020-2, p. 317–336

Climate-induced warming increasingly leads to degradation of high-alpine permafrost. In order to develop early warning systems for imminent slope destabilization, knowledge about hydrological flow processes in the subsurface is urgently needed. Due to the fast dynamics associated with slope failures, non- or minimally invasive methods are required for inexpensive and timely characterization...

Université de Neuchâtel

Conditioning groundwater flow parameters with iterative ensemble smoothers : analysis and approaches in the continuous and the discrete cases

Lam, Dan-Thuy ; Renard, Philippe (Dir.) ; Kerrou, Jaouher (Codir.)

Thèse de doctorat : Université de Neuchâtel, 2019.

Data assimilation (DA) consists in combining observations and predictions of a numerical model to produce an optimal estimate of the evolving state of a system. Over the last decade, DA methods based on the Ensemble Kalman Filter (EnKF) have been particularly explored in various geoscience fields for inverse modelling. Although this type of ensemble methods can handle high-dimensional systems,...

Université de Neuchâtel

Statistical metrics for the characterization of karst network geometry and topology

Collon, P ; Bernasconi, D ; Vuilleumier, C ; Renard, Philippe

In: Geomorphology, 2017, vol. 283, p. 122-142

Statistical metrics can be used to analyse the morphology of natural or simulated karst systems; they allow describing, comparing, and quantifying their geometry and topology. In this paper, we present and discuss a set of such metrics. We study their properties and their usefulness based on a set of more than 30 karstic networks mapped by speleologists. The data set includes some of the largest...

Université de Neuchâtel

On the use of multiple-point statistics to improve groundwater flow modeling in karst aquifers : A case study from the Hydrogeological Experimental Site of Poitiers, France

Le Coz, M ; Bodin, J ; Renard, Philippe

In: Journal of Hydrology, 2017, vol. 545, p. 109-119

Limestone aquifers often exhibit complex groundwater flow behaviors resulting from depositional heterogeneities and post-lithification fracturing and karstification. In this study, multiple-point statistics (MPS) was applied to reproduce karst features and to improve groundwater flow modeling. For this purpose, MPS realizations were used in a numerical flow model to simulate the responses to...

Université de Fribourg

Multi-proxy facies analysis of the Opalinus Clay and depositional implications (Mont Terri rock laboratory, Switzerland)

Lauper, Bruno ; Jaeggi, David ; Deplazes, Gaudenz ; Foubert, Anneleen

In: Swiss Journal of Geosciences, 2018, vol. 111, no. 3, p. 383–398

Located in NW Switzerland, the Mont Terri rock laboratory is a research facility primarily investigating the Opalinus Clay as potential host rock for deep geological disposal of radioactive waste. In the Mont Terri area, this Jurassic shale formation is characterized by three distinctive lithofacies: a shaly facies, a carbonate-rich sandy facies and a sandy facies. However, the lithological...