Aims: characterize the nature (lithologies, dimensions, distribution of key kinematic and physical properties) and provide high-resolution imaging of the plate interface through integration of field evidence, detailed temperature-depth-time-fluid rock trajectories, active seismic imaging, seismological and geodetic monitoring. Detailed targets:

1- physical properties of the plate interface zone as recovered from the rock record of exposed plate interface zones, active source seismic imaging, seismology/high resolution tomography

2- kinematic characteristics at the plate interface zone (and their spatial and temporal scaling properties) as inferred by geodetic observations, as well as the range of deformation transients observed, and how they relate with the physical properties and the seismic cycle

3- (transient) petrophysical properties of the downgoing slab and the overlying upper plate, and the extent to which fluid is circulated and/or permeability boundaries exist

4- correlations between coseismic rupture, aftershocks and afterslip, interseismic locking and seismicity and the short-term rheological properties estimated from petrological, kinematic and seismological observables.

Aims: quantify (1) fluxes of fluid and mass through and along the plate interface by bridging space and time scales through the combination of field data, geochemical and isotopic analysis and modelling, and (2) the relationships between reactions, fluid flow, seismicity and mobilization of both major and trace elements from the various rock sources.  Detailed targets:

1- relationships between the distinct deformation structures and fluid/mass transfer, and characterization of fluid migration processes (ie, distributed porous flow or channelised fluid flow)

2- determination of the spatial and temporal scales of fluid flow and associated deformation processes

3- interrelations between flow patterns and chemical-petrophysical changes in the rocks

4- determination of the contribution, through space and time, of the various fluid/mass sources (ie, the dehydrating slab mantle, oceanic crust or sediments ± melts) to the overall flux of energy and matter at the plate interface.

Aims: calibrate both rheology and mechanical coupling of plates at various scales, for both transient (10⁴yrs) and long-lasting processes (10^1-7yrs), through a combination of structural and experimental work, monitoring and fully coupled thermodynamic-thermomechanical modelling. Detailed targets:

1- understanding the links between rock deformation/fracture mechanisms along the interface and the temporal scale of frictional mechanical coupling. More generally, links between long-lived deformation processes along the interface and megathrust earthquakes generation, and between fluid flow and seismic coupling during the seismic cycle

2- understanding how post-seismic deformation is generated after large subduction earthquakes (ie, predominantly viscoelastic relaxation in the asthenosphere or aseismic afterslip on the subduction interface?), and its consequences on tectonic concepts (rigid plate and long term vs. short term velocities) and seismic hazard quantification. The three giant earthquakes which occurred since 2004 will help to clarify this controversy

3- rheological behavior of the lower and upper (mantle wedge) plate boundaries and their evolution as a function of depth (ie, from strong to increasingly weak?) and time.