Description du projet
Les déformations des roches et le rôle des fluides à plusieurs échelles de temps et de distance
De la formation des montagnes aux tremblements de terre, les mouvements dynamiques de la Terre ferme sur de courtes et longues échelles de temps sont, de manière peut-être surprenante, régis par l’eau. Les forces physiques et les réactions chimiques liées à la présence d’eau à différentes profondeurs dans la Terre jouent un rôle, mais leurs mécanismes et leurs effets quantitatifs sont encore mal connus. Le projet RockDeath, financé par le CER, se propose d’identifier et de quantifier les processus mécaniques, hydrauliques et chimiques couplés qui se produisent dans la lithosphère et le rôle que jouent les fluides à différentes profondeurs dans des dynamiques rapides et lentes. Cette étude sera menée en laboratoire à l’aide d’expériences de déformation des roches, avec des instruments et des méthodes de traitement des données à la pointe de la technologie.
Objectif
The dynamics of the solid Earth, e.g. the initiation of plate tectonics, the strength of plate boundaries, and the formation and evolution of mountains, is directly controlled by the chemical and physical action of water. In the shallow (brittle) part of the lithosphere, fluid pressure counteracts the lithostatic pressure and weakens faults. At greater depth, the chemical activity of water makes rocks plastically weaker, and is also responsible for metamorphic reactions that induce weakening. Fluids have been invoked to explain observations of tremor and slow slip at depth, and a large fraction of crustal seismicity is attributed to upward fluid flow, inducing earthquake swarms.
Yet we still have very few quantitative constraints on either fluid pressure or chemical activity of water at depth in the lithosphere. In addition, fluid pressure and transport are coupled to deformation, and the mechanisms by which fluids induce fault slip and seismicity are not well understood: crustal fluids are very mobile, and rock physical properties evolve in response to both fluid-rock interactions and deformation.
The aim of this project is to identify and quantify the coupled mechanical, hydraulic and chemical processes occurring across the lithosphere, from slow creep to rapid earthquake slip, and determine the role played by fluids on deep and shallow seismicity, slow slip, and long-term evolution of plate boundaries.
I propose to conduct laboratory rock deformation experiments with state-of-the-art instrumentation and data processing methods to determine the spatio-temporal evolution of fluid flow and seismicity during faulting, quantify the evolution of rock physical and transport properties during long-term ``healing'', and test how chemical water activity and metamorphic hydration reactions impact deep fault rheology. The laboratory data will allow us to establish the geophysical signature of fluids in the lithosphere, and how they impact the dynamics of faults.
Champ scientifique
Programme(s)
- HORIZON.1.1 - European Research Council (ERC) Main Programme
Régime de financement
HORIZON-ERC - HORIZON ERC GrantsInstitution d’accueil
14473 POTSDAM
Allemagne