Seminar: Stochastic Modeling of the Earth Subsurface: Dealing with Unobserved Natural Systems
Many hydrological processes taking place at the Earth’s surface are directly observable, either through
in-situ measurements or by using remote sensing techniques. In contrast, understanding properties of the
subsurface poses formidable observational challenges. Firstly, measurements of the Earth’s interior are
either difficult and expensive to acquire (e.g., boreholes) or indirect (e.g., measurement of subsurface flow
and tracer concentrations). Secondly, the Earth’s interior is 3-dimensional, resulting in very empty data
spaces. For example, even intensive drilling campaigns and geophysical surveys of an aquifer often sample
only a small fraction of the total rock volume.
This talk will present stochastic aquifer modeling approaches that allow quantifying uncertainty in such
data-poor problems. For many practical questions, the uncertainty in subsurface hydraulic properties further
propagates into uncertainty in water resources management problems—for example, the transport of
contaminant to a drinking water well, the intake of a groundwater-based desalination plant, or the behavior
of a tracer in a subglacial drainage system. Stochastic aquifer models allow using a statistical description
of the unobserved system to formulate ensemble predictions, resulting in a distribution of possible outcomes.
The use of stochastic models will be illustrated in different environments, focusing on applications that
integrate indirect data through inverse approaches.
Grégoire Mariéthoz’s research and teaching areas revolve around geostatistics, image processing, data analysis
methods and their application to earth observation, remote sensing, hydro(geo)logy and inverse problems. He is
currently the Adjunct Director and Professor at the Institute of Earth Surface Dynamics, University of Lausanne,
Switzerland. Mariéthoz is also the Director of the Swiss Geocomputing Centre.
Adjunct Director and Professor at the Institute of Earth Surface Dynamics, University of Lausanne, Switzerland and Director of the Swiss Geocomputing Centre
Dr. Grégoire Mariéthoz