Programme des sessions > Recherche par auteur correspondant > Thomas Marion

Natural fault zones are complex structures. While there are strong variations
from one outcrop to another, they all share a common characteristic: a non-
planar fault core, where extensive shearing is observed, surrounded by
pervasively fractured rocks that lack significant displacement. Recent
observations have highlighted that this overall structure, from the properties
of the fault core to the rheology of the damage zone, influences the modes of
deformation (seismic and aseismic) and the total amount of slip.
Using a micromechanics-based constitutive model that accounts for off-fault
damage at high strain rates, we show that the off-fault damage structure
carries information about the rupture dynamics itself. This discovery opens
new avenues to revisit past earthquakes. We consider 2D in-plane ruptures
on rough faults with root mean square (rms) height fluctuations of the order
of 10^-3 to 10^-2 times the profile length. We explore the dynamic effects of
fault roughness on off-fault damage structure and earthquake rupture
dynamics. Our findings demonstrate that the co-seismic damage zone
structure embeds details of the fault rupture dynamics, which in turn affects
strong ground motion. This opens up a novel approach to infer or invert
rupture velocity variation from natural observations of co-seismic damage,
whether from historical earthquakes or more recent ones with high-resolution
co-seismic damage measurements.