Winter winds and volcanic ash: Seasonal controls and modern hazards using past distal S1 tephra dispersal from Mt. Erciyes

Explosive volcanic eruptions can generate widespread hazards, particularly ash plumes, capable of disrupting societies far beyond the source volcano. Ash dispersal can be strongly controlled by seasonal atmospheric circulation. Distal volcanic ash (tephra) layers preserved within annually-layered sediments (varves) can provide chronological control and seasonal insights into past eruptions and atmospheric regimes responsible for ash dispersal, allowing for the assessment of past climatic regimes at seasonal resolution and future hazard insight.

Southwest Asia hosts several active volcanic centers. Yet, widespread ash plume impacts in this region remain largely overlooked in hazard assessments. The annually-laminated lacustrine record of the ICDP Dead Sea core (5017-1A) provides a unique opportunity to reconstruct such hazard scenarios in the past at seasonal resolution. Here, we present the identification of the S1 tephra from Mt. Erciyes (Central Anatolian Volcanic Province, Turkey) dated to ~8.9 kya, as a microtephra layer preserved within a winter flood layer of the Dead Sea record. This unique finding provides the first direct evidence for the seasonal timing of the S1 eruption. Major and trace element geochemical analysis allows for robust correlations between the Dead Sea and other distal tephra sites in the region. By integrating this regional tephra network with Ash3D model for ash plume dispersal, we reconstructed the past winter atmospheric circulation pattern that allowed the transport of the ash southwards from Central Anatolia. The model results show that only specific winter circulations and plume heights reproduce the observed tephra distribution, tightly constraining both eruption dynamics and seasonal atmospheric behavior. These results allow for modern hazard analogues and potential widespread impacts to be inferred if Mt. Erciyes were to erupt under the same atmospheric conditions today. Overall, this study demonstrates that combining seasonally resolved tephra records with ash dispersal modelling provides new constraints on past eruption impacts and atmospheric circulation, offering a framework for assessing future explosive eruption hazards in an underrepresented, yet highly vulnerable region.