This project aims at constraining models of present-day intracontinental deformation in the Altai-Sayan range in South Siberia, using GPS geodesy, absolute gravimetry, and structural analysis. Estimation of horizontal and vertical velocities of the active crustal movements in the Altai-Sayan mountain region are done using GPS space geodesy and gravimetry, supported by a combination of existing geological and geophysical studies. The main targets are: 1 - to measure the present-day crustal deformation and compare it with geological estimates; 2 - to determine the neotectonic block structure, relative block movements, estimate slip direction and slip rates on major active fault, estimate elastic strain accumulation, and compare with seismological results; 3 - to integrate the velocity and deformation fields at a broader scale, together with available results obtained in the Tian Shan and the Baikal rift zone; 4 - to test and validate crustal deformation models using the new field constraints; 5 - to contribute defining the potential seismic and tectonic risks in the Gorny-Altai, and Tuva Autonomous Republics and to draw guidelines for hazard assessment and mitigation.