Abstract
To study the sensitivity of surface observables to subduction and mantle flow, i.e. the coupling of crustal tectonics and the underlying mantle dynamics, we have developed 3D numerical models of the instantaneous crust-mantle dynamics of the eastern Mediterranean. These models comprise both a realistic crust-lithosphere system and the underlying mantle. For this presentation we focus on the regional crustal flow response to the present-day Aegean subduction system.
The set-up of our curved model domain measuring 40°x40°x2900km is based on geological and geophysical data of the eastern Mediterranean. We first create a 3D synthetic geometry of the crust-lithosphere system, including the present-day plate configuration and crust and lithosphere thickness variations. Next the geometry of the Aegean slab is constructed from a seismic tomography model and earthquake hypocenters. The combined geometries are then imported into the finite element code ASPECT (Heister et al. 2017, Geophys. J. Int., 210).
The mantle initial temperature conditions can include deviations from an adiabatic profile obtained from conversion of seismic velocity anomalies using a depth-dependent scaling. We model compressible mantle flow for which material properties are obtained from thermodynamics lookup-tables in combination with a nonlinear viscoplastic rheology. Relative or absolute plate motion velocities are prescribed at the model sides, while a free-slip surface accommodates internal deformation. In short, forcing in our models comprises lateral pressure gradients, mantle buoyancy and forcing related to the prescribed plate motions.
Based on the above initial and boundary conditions, we obtain model predictions of the regional flow field. Focusing on the crust, these represent predictions of the GPS velocity field that we can compare to actual GPS data. Our initial model predictions provide a good overall fit. Subsequent models include constructed variations in slab morphology, mantle structure and boundary conditions that either improve or lessen our fit to the GPS velocity field and help determine the controls of mantle dynamics on present-day tectonic deformation in the Aegean region. This then enables us to characterize the general sensitivity of surface observables to plate motions, mantle flow and slab dynamics.
The set-up of our curved model domain measuring 40°x40°x2900km is based on geological and geophysical data of the eastern Mediterranean. We first create a 3D synthetic geometry of the crust-lithosphere system, including the present-day plate configuration and crust and lithosphere thickness variations. Next the geometry of the Aegean slab is constructed from a seismic tomography model and earthquake hypocenters. The combined geometries are then imported into the finite element code ASPECT (Heister et al. 2017, Geophys. J. Int., 210).
The mantle initial temperature conditions can include deviations from an adiabatic profile obtained from conversion of seismic velocity anomalies using a depth-dependent scaling. We model compressible mantle flow for which material properties are obtained from thermodynamics lookup-tables in combination with a nonlinear viscoplastic rheology. Relative or absolute plate motion velocities are prescribed at the model sides, while a free-slip surface accommodates internal deformation. In short, forcing in our models comprises lateral pressure gradients, mantle buoyancy and forcing related to the prescribed plate motions.
Based on the above initial and boundary conditions, we obtain model predictions of the regional flow field. Focusing on the crust, these represent predictions of the GPS velocity field that we can compare to actual GPS data. Our initial model predictions provide a good overall fit. Subsequent models include constructed variations in slab morphology, mantle structure and boundary conditions that either improve or lessen our fit to the GPS velocity field and help determine the controls of mantle dynamics on present-day tectonic deformation in the Aegean region. This then enables us to characterize the general sensitivity of surface observables to plate motions, mantle flow and slab dynamics.
| Original language | English |
|---|---|
| Publication status | Published - 15 Dec 2017 |
| Event | AGU Fall Meeting 2017 - New Orleans, United States Duration: 11 Dec 2017 → 15 Dec 2017 https://fallmeeting.agu.org/2017/# |
Conference
| Conference | AGU Fall Meeting 2017 |
|---|---|
| Abbreviated title | AGU Fall Meeting 2017 |
| Country/Territory | United States |
| City | New Orleans |
| Period | 11/12/17 → 15/12/17 |
| Internet address |