Rheologies for the Earth’s brittle crust
Orateur : Jean-Arthur Olive – ENS, Paris
Abstract : Most of the brittle, earthquake-generating deformation that shapes mountain ranges takes place in the uppermost 15 km of the Earth’s crust. On short time scales, the upper crust deforms by slip on frictional faults that delineate elastic blocks. Over millions of years, however, large non-recoverable deformation accumulates both on and off-faults, and distributed brittle strain can localize to form new fault systems. This complex rheological behavior is typically modeled as Mohr-Coulomb elasto-plasticity, with a range of ad-hoc softening parameters that lack a clear micro-mechanical interpretation. I will discuss possible adjustements to this framework aimed at (1) better capturing key properties of crustal rocks inferred from laboratory experiments, and (2) better representing the mineral-scale processes which underlie brittle failure. Improved constitutive laws for the brittle upper crust are a necessary step towards a unified description of geological processes, from mineral to crustal scale, and from seconds to millions of years.
Date et lieu : le vendredi 24 juin 2022 – 11h salle 250 / IUSTI
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