Tree-ring based record of intra-eruptive lahar activity: Axaltzintle valley, Malinche volcano, Mexico

Lahars are a widespread phenomenon in volcanic environments and good knowledge generally exists on contemporary, syn-eruptive lahar activity. Much less data is, by contrast, available on post-eruptive lahars and/or hydrogeomorphic processes out of extinct volcanic complexes. In this study we present a reconstruction of intra-eruptive lahar activity in Axaltzintle valley (Malinche volcano) using growth-ring records of 86 Abies religiosa trees. Based on the identification of 217 growth disturbances, field evidence and hydrological records we reconstruct a total of 19 lahars for the period 1945–2011. The reconstructed lahars were mostly triggered by moderate intensity, but persistent rainfalls with sums of at least ~100 mm. By contrast, the 1998 and 2005 lahars were presumably triggered by hurricane-induced torrential rainfalls with >100 mm in three days