Tectonic control over the abuli samsari volcanic ridge, lesser caucasus, Georgia

The purpose of the present work is to integrate previous research focused on the Abuli Samsari Volcanic Ridge, situated in the Javakheti Highland, Georgia. Through a synergic approach, consisting in the collection and analysis of field and satellite data, combined with the results of previously published research, we have been able to define the overall structure of the volcanic ridge, which, on its northern sector, is cut across by two parallel pipelines, carrying oil and gas from the Caspian Sea to the western countries. Despite the likelihood of seismic or volcanic events in the area, geohazard assessment had never been adequately performed for this section of the pipelines’ route across Southern Georgia. The most relevant outcomes of our effort, aimed at filling this critical gap, consist in: the identification and mapping of eruptive centers and tectonic lineaments; the reconstruction of magma pathways; the definition of the expected moment magnitude for possible earthquakes; the assessment of orientation of the maximum horizontal stress from the Late Miocene to the present day. We have used these results to evaluate the current seismic and volcanic hazards affecting the Abuli Samsari Volcanic Ridge, which may have major impacts on the security of the pipelines. The calculated, about N-S directed maximum horizontal stress may play a key role in volcanic reactivation, which might occur in the form of fissure eruptions and the formation of new vents and monogenetic as well as composite volcanoes. As the track of the pipelines lies just north of the younger volcanic edifice in the ridge we suggest that these lifelines could be severely affected by possible future volcanic eruptions, which might bring about a major interruption in oil delivery from the Caspian Sea towards the west.