BULLETIN OF VOLCANOLOGY, no.7, 2024 (SCI-Expanded)
Hasandag volcano (Central Anatolia, Turkey) has recently underwent an increase in local seismicity and fumarolic activity since 2013. In the past, this volcano has produced multiple large explosive eruptions during the last million years. The Belbashani Pumice is the product of a sub-Plinian to Plinian eruption dated at similar to 417 +/- 20.5 ka (Ar-40/Ar-39). Here, we present a complete volcanological study including stratigraphy, glass chemistry, pumice morphology, geochronology, and eruption source parameters with the associated uncertainties, to characterize the Belbashani Pumice eruption. The eruption involved a column of 18-29 km in height, with the main dispersal axis towards the northeast. A pumice layer up to similar to 17-m-thick accumulated in proximal deposits along the Belbashani path, and up to 2-m-thick in medial-distal areas (similar to 18 km northeast from the vent). The high and tubular vesicularity of the pumice clasts indicates that the Belbashani eruption was predominantly magmatic. The bulk volume of the Belbashani Pumice fallout deposit has been estimated as 0.5 and 8 km(3) (with similar to 2 km(3) being the mean value), which corresponds to Volcanic Explosivity Index (VEI) of at least 4 and up to 6. Both isopach and isopleth maps indicate that the volcanic vent may have been located at the intersection of the Tuz Golu fault and Ulukisla caldera, within the Hasandag volcanic complex. The glass composition of Belbashani Pumice confirms that the eruption belongs to the Hasandag magmatic system. The reconstruction of the Belbashani Pumice eruption represents an essential baseline in providing volcanological constraints for further investigations of tephra fallout hazard assessment in Central Anatolia, especially considering that a new Plinian eruption cannot be ruled out at Hasandag volcano in the future. The chemical and geochronological datasets presented here could aid in refining tephrochronological correlations, with the goal of synchronizing paleoenvironmental and paleoclimatic records alongside archaeological sites.