ИСТИНА

We present an updated velocity field for the Caucasus collision zone building on earlier observations (1991-2008) and incorporating new observations from more recent initiatives. All GPS data were processed uniformly using the GAMIT/GLOBK software suite, combining survey mode data with data from continuous stations in the region. The 2012 velocity field includes approximately 120 sites distributed throughout the Greater and Lesser Caucasus Mountains with velocity uncertainties sufficient for tectonic analysis, roughly doubling the number from our prior solution (2008). Velocity uncertainties for many prior reported sites are now < 0.5 mm/yr. Four GPS profiles crossing the Main Caucasus Thrust (MCT) Fault are located near longitude 49.5°E (near Baku, Az), 48.5°, 44.5° (near Tbilisi, Georgia), and 43.5°. The trans-Caucasus profile near 44.5° extends across the full Lesser and Greater Caucasus encompassing roughly 8-9 mm/yr of total convergence with average station spacing of ~17 km, and ~11 km across the Greater Caucasus. Improved secular velocities will allow better estimates of slip rates, locking depths, and the degree of coupling on major faults associated with convergence across the mountain system (particularly the MCT), and possible internal strain and rotation of crustal blocks within the collision zone.