Subduction Dynamics and their Kinematic Expression
Subducting slabs are the main driving force in mantle convection. Much has been learned about the role of subducting plate by studying plate kinematics (i.e. motions and dips as they evolve through time). But many questions remain about why plates attain the dip they have, what the role of the overriding plate is and how kinematics and dynamics relate to earthquake potential, especially of the large earthquakes along the subduction interface. Aim of this work is to obtain insight in how present and past subduction kinematics relate to dynamics. We do this by a combination of dynamic and thermo-kinematic modeling, kinematic reconstructions and comparison with seismic tomography, plate motions and seismicity. Specific attention has gone into studying subduction processes in the Central and Western Mediterranean and under western North America.
This figure shows the evolution of the (von Mises) stress in a 1000 km wide subducting plate. The plate subducts under its own buoyancy and encounters only passive resistance from the surrounding (upper) mantle. It flattens out above the 30-fold viscosity increase between upper and lower mantle. Such plates subduct predominantly through rollback and attain a balance between subduction velocity, dip and roll back velocity that minimizes overall energy dissipation (from Capitanio et al., 2007)
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- Fabio A. Capitanio (Monash University)
- Gabriele Morra (Eth Zurich/Roma Tre)
- Maria Seton (Univ. Sydney)