Testing the ‘Laacher See hypothesis’: a health hazard perspective

It has recently been suggested that the Laacher See volcanic eruption, which occurred around 13,000 years ago, initiated significant demographic fluctuations along the northern periphery of Late Glacial human settlement and that these led to a number of material culture transformations. The origins of the Southern Scandinavian Bromme culture and the northeastern European Perstunian culture as well as the temporary abandonment of Central European regions have been linked to this eruption. However, it remains unclear precisely which aspects of the eruption stimulated Late Glacial foragers to abandon their traditional ways of life. Paradoxically, the culture–historical impact of the eruption appears greater further away from the eruptive centre. Here, we investigate one potential middle-range link between the Laacher See eruption and Late Glacial fauna and foragers: tephra as a health hazard. We use laser-diffraction particle-size analysis to quantitatively investigate tephra from one site with a secure Late Glacial archaeological deposit. In addition, we use values previously reported in the literature and a predictive model to calculate the hazard potential along a transect of two of the three major Laacher See tephra fans. Our results show that the Laacher See tephra may have posed a potential health hazard and that its hazard potential may have increased with distance from the vent. To our knowledge this is the only study that attempts to quantify the changing grain-size composition of tephra fall-out longitudinally in this way, at least with regard to a prehistoric eruption. We close by discussing, more speculatively, other possible health-pertinent effects of the Laacher See eruption and suggest ways in which future work can further evaluate the impact of this eruption on Late Glacial populations.