HR: 11:35h
AN: T12A-06    [Abstracts]
TI: Developing Tools to Test the Thermo-Mechanical Models, Examples at Crustal and Upper Mantle Scale
AU: * Le Pourhiet, L
EM: laetitia@gps.caltech.edu
AF: california institute of technology, 1200 E california ave, PASADENA, Ca 91106 United States
AU: Yamato, P
EM: philippe.yamato@lgs.jussieu.fr
AF: UPMC, 4 place Jussieu, Paris, 75005 France
AU: Burov, E
EM: burov@lgs.jussieu.fr
AF: UPMC, 4 place Jussieu, Paris, 75005 France
AU: Gurnis, M
EM: gurnis@gps.caltech.edu
AF: california institute of technology, 1200 E california ave, PASADENA, Ca 91106 United States
AB: Testing geodynamical model is never an easy task. Depending on the spatio-temporal scale of the model, different testable predictions are needed and no magic reciepe exist. This contribution first presents different methods that have been used to test themo-mechanical modeling results at upper crustal, lithospheric and upper mantle scale using three geodynamical examples : the Gulf of Corinth (Greece), the Western Alps, and the Sierra Nevada. At short spatio-temporal scale (e.g. Gulf of Corinth). The resolution of the numerical models is usually sufficient to catch the timing and kinematics of the faults precisely enough to be tested by tectono-stratigraphic arguments. In active deforming area, microseismicity can be compared to the effective rheology and P and T axes of the focal mechanism can be compared with local orientation of the major component of the stress tensor. At lithospheric scale the resolution of the models doesn't permit anymore to constrain the models by direct observations (i.e. structural data from field or seismic reflection). Instead, synthetic P-T-t path may be computed and compared to natural ones in term of rate of exhumation for ancient orogens. Topography may also help but on continent it mainly depends on erosion laws that are complicated to constrain. Deeper in the mantle, the only available constrain are long wave length topographic data and tomographic "data". The major problem to overcome now at lithospheric and upper mantle scale, is that the so called "data" results actually from inverse models of the real data and that those inverse model are based on synthetic models. Post processing P and S wave velocities is not sufficient to be able to make testable prediction at upper mantle scale. Instead of that, direct wave propagations model must be computed. This allows checking if the differences between two models constitute a testable prediction or not. On longer term, we may be able to use those synthetic models to reduce the residue in the inversion of elastic wave arrival time
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: Fall Meeting 2005