Based on the large amount of space geodetic data (20 years of GNSS permanent measures and InSAR) and seismic data (Sismalp, 30 years) that are now available, this work aims at establishing a high-resolution 3D deformation field of the upper crust in the western Alps. This deformation field will locate the boundary of the Eurasian plate in the distributed deformation zone of the Alpine arc, and help to discuss the relative role of potential geodynamic motors of current deformation which are (1) plate tectonics with the rotating Adriatic plate relative to the stable Europe, and (2) volume forces intrinsic to the Alpine crust (post-glacial rebound, erosional unloading, isostatic imbalance due to the lithosphere-mantle interaction, eg. slab detachment). This thesis will be in synergy with the ANR Alparray (coordinator Anne Paul, ISTerre Grenoble) which will establish by a high-resolution seismic tomography an accurate picture of the deep structures of the Alps. The simultaneous availability of our 3D deformation field of the upper crust and the geometry of the deep structures will lead to innovative results on the motors of deformation in slow orogenic context. The results also provide valuable data for characterization of regional seismic hazard.