Structural model of the Mtskheta 1275 (Mw=6.5) historical earthquake epicentral area using seismic profiles, Georgia

We have presented a new structural model of the Mtskheta 1275 (Mw=6.5) historical earthquake epicentral area. The Mtskheta historical earthquake is located in the frontal part of the Lesser Caucasus orogen pro-wedge (Alania, V., et al., 2023). The frontal part of the Lesser Caucasus orogen is characterized by moderate seismic activity (e.g., Tsereteli et al., 2016). From the determination of the deep structure of the Mtskheta 1275 (Mw=6.5) historical earthquake epicentral area, we use seismic reflection profiles. Seismic reflection profiles show north-vergent duplexes, and structural wedge at the triangle zone beneath the thrust front monocline and is represented by Cretaceous-Neogene strata. In the southern part of the Kura foreland basin, the Oligocene-Lower Miocene strata have been deformed and uplifted by passive-back thrusting at the triangle zone. Based on the new structural model, it has been suggested that the Mtskheta 1275 (Mw=6.5) historical earthquake was related to structural wedge. The results of our subsurface interpretations have important implications for how this fold-and-thrust belt formed, in addition to the effect of structural style on active tectonics in the retro-wedge of the Lesser Caucasus orogen.

Acknowledgments. This work was funded by Shota Rustaveli National Science Foundation (SRNSF) (grant# FR-23-8896).