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Girard L.,University of Zurich | Weiss J.,CNRS Laboratory for Glaciology and Environmental Geophysics | Amitrano D.,CNRS Institute of Earth Sciences
Physical Review Letters | Year: 2012

We investigate compressive failure of heterogeneous materials on the basis of a continuous progressive-damage model. The model explicitly accounts for tensile and shear local damage and reproduces the main features of compressive failure of brittle materials like rocks or ice. We show that the size distribution of damage clusters, as well as the evolution of an order parameter-the size of the largest damage cluster-argue for a critical interpretation of fracture. The compressive failure strength follows a normal distribution with a very small size effect on the mean strength, in good agreement with experiments. © 2012 American Physical Society. Source


Zuddas P.,CNRS Institute of Earth Sciences
Elements | Year: 2010

The chemical composition of groundwater results from the reaction of mineral dissolution and precipitation. We can use the thermodynamic approach to predict water composition under conditions where water and newly formed minerals are in equilibrium. Although some minerals exist in a state of equilibrium with water, other minerals are always unstable. In the latter case, we can evaluate the extent of the overall irreversible mass transfer between minerals and water to quantify the mineral surface area participating in the water-rock interaction. This parameter is fundamental to basic and applied research in areas such as the geological sequestration of CO2 and the safe geological storage of waste. Source


Braun J.,CNRS Institute of Earth Sciences | Willett S.D.,ETH Zurich
Geomorphology | Year: 2013

We present a new algorithm to solve the basic stream power equation, which governs channel incision and landscape evolution in many geomorphic settings. The algorithm is highly efficient because computation time increases linearly with the number of points used to discretize the landscape and is ideally suited to parallelization. It is also unconditionally stable because it uses an implicit scheme for the time integration of the landscape evolution equation, which means that large time steps can be used without sacrificing accuracy. In this paper we describe the algorithm and present results that demonstrate its efficiency and accuracy. © 2012 Elsevier B.V. Source


Based on a review of published literature and on the report of a few case studies, this paper summarizes the state of the art on paleostress determinations by fault slip data inversions, with the aim at discussing whether these techniques actually yield a quantity that has a " paleostress meaning" (i.e., ancient stress) and whether there is an adequate basis for a reliable comparison of such " paleostresses" with contemporary stresses in terms of orientations and patterns at different scales of time and space in the Earth's crust. © 2012 Académie des sciences. Source


Snieder R.,Colorado School of Mines | Larose E.,CNRS Institute of Earth Sciences
Annual Review of Earth and Planetary Sciences | Year: 2013

Recent research has shown that noise can be turned from a nuisance into a useful seismic source. In seismology and other fields in science and engineering, the estimation of the system response from noise measurements has proven to be a powerful technique. To convey the essence of the method, we first treat the simplest case of a homogeneous medium to show how noise measurements can be used to estimate waves that propagate between sensors. We provide an overview of physics research-dating back more than 100 years-showing that random field fluctuations contain information about the system response. This principle has found extensive use in surface-wave seismology but can also be applied to the estimation of body waves. Because noise provides continuous illumination of the subsurface, the extracted response is ideally suited for time-lapse monitoring. We present examples of time-lapse monitoring as applied to the softening of soil after the 2011 Tohoku-oki earthquake, the detection of a precursor to a landslide, and temporal changes in the lunar soil. © Copyright ©2013 by Annual Reviews. All rights reserved. Source

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