Active crustal-scale duplexes and structural wedge in the central part of Greater Caucasus orogen pro-wedge, Georgia

The Greater Caucasus orogen is a typical active double wedge orogen that accommodates the crustal shortening due to far-field effects of the collision between the Arabian and Eurasian plates. Our study area is a central part of the Greater Caucasus pro-wedge and represented by the Dzirula-Imereti Uplift zone and epicentral area of Racha 1991 (MW=7) and 2009 (MW=6) earthquakes - Southern Slope of Greater Caucasus. Here we present a new structural model based on interpreted seismic profiles and regional balanced cross-sections. Seismic reflection data reveals the presence of a basement structural wedge, fault-related folds, triangle zones, and active- and passive-roof duplexes. The most important observation from our study is that the Dzirula massif is a basement wedge and forms a triangle zone. The Dzirula structure is defined by mid-crustal detachment and a roof thrust, constituting a tectonic wedge with a passive back thrust. The regional balanced cross-sections show that the Racha earthquakes are related to crustal-scale duplexes. Acknowledgments. This work was funded by Shota Rustaveli National Science Foundation (SRNSF) (grant# FR-21-26377).