Earthquakes as collapse precursors at the Han-sur-Lesse Cave in the Belgian Ardennes

Lamina counting of a stalagmite growing on the 1828 debris dates the collapse at 1826 ± 9 CE, demonstrating the possibility of dating previous collapses with a few years of uncertainty. Furthermore, our study opens new perspectives for studying collapses and their chronology both in the Han-sur-Lesse Cave and in other karstic networks. We suggest that earthquake activity could play a stronger role than previously thought in initiating cave collapses.