Resumen
Sediment cores from lakes and bogs in the Río Cisnes valley contain tephra from explosive eruptions of
volcanoes in the southern part of the Andean Southern Volcanic Zone (SSVZ). These tephra, which thicken and coarsen
to the west, are attributed to eruptions from Melimoyu, Mentolat, Hudson, and potentially either Macá, Cay or one of
the many minor eruptive centers (MEC) located both along the Liquiñe-Ofqui Fault Zone (LOFZ) and surrounding
the major volcanoes. Correlation of the tephra between two new cores in the lower Río Cisnes valley, and amongst
other cores previously described from the region, and source volcano identification for the tephra, has been done using
lithostratigraphic data (tephra layer thickness and grain size), petrography (tephra glass color, vesicle morphology,
and type and abundance of phenocryst phases), and by comparison of bulk tephra trace-element characteristics with
previously published whole-rock and bulk tephra chemical analysis. Four tephras in these cores are attributed to eruptions
of Mentolat, four to eruptions from Melimoyu, one possibly to Hudson, and six cannot be assigned to a specific source
volcano. Some of these tephra correspond to pyroclastic tephra fall deposits previously observed in outcrop, including the
MEL2 eruption of Melimoyu and the MEN1 eruption of Mentolat. However, others have not been previously observed
and represent the products of newly identified small to medium sized eruptions from volcanoes of the SSVZ. These
results provide new information concerning the frequency and magnitude of explosive eruption of SSVZ volcanoes and
contribute to the evaluation of volcanic hazards in the region