Crustal deformation of the Azerbaijan territory: results from 25 years (1998 - 2022) of monitoring using GPS

We present GPS observations of crustal deformation monitoring in Azerbaijan and adjacent territory which carried out since 1998. Unlike our previous studies there are more permanent GPS station and survey mode data aggregated, which accordingly allowed us more accurately determine the dynamics of the main tectonic structures. Eight permanent stations were established by the Institute of Geology and Geophysics since 2006. In 2012, Republican Seismological Survey Center of Azerbaijan National Academy of Sciences started to construct permanent GPS stations, where totally 24 stations were established. Over 35 survey mode sites were measured repeatedly starting from 1998 to 2022. On a broad scale, the GPS velocity field clearly illustrates the NNE motion of Caucasus and adjacent regions with respect to Eurasia south of the Main Caucasus Thrust Fault (MCT). An important note here is the sharp decrease in site velocities, and the clockwise rotation, between sites located to the west of West Caspian Fault (WCF) in Kura Depression and Talish region and sites to the east of WCF in Absheron Peninsula. This decrease and difference in GPS vector directions indicate high strain accumulation rates ~6 mm/yr south to Absheron Peninsula. We believe that the significant accumulation of elastic energy is responsible for the activation of seismic events and of mud volcanoes in this region. Thus, spatial densification of the GPS observations is needed to better resolve localized deformation, and consequently the seismic hazard in the eastern Caucasus, Kur Depression, and Absheron area.