Reconstruction of the AD 1600 Huaynaputina eruption based on the correlation of geologic evidence with early Spanish chronicles

Abstract

The largest historical eruption (VEI 6) in the Andes began on February 19 and continued until March 6 or 15, AD 1600 at Huaynaputina, a dacitic stratovolcano located on a high volcanic plateau in south Peru. Tephra falls, pyroclastic flows and surges disrupted life in an area of ∼4900 km2 around the volcano, and ash-fall was reported 200–500 km away in south Peru, west Bolivia, and north Chile. The aftermath of the large-scale eruption was severe and protracted for the people and colonial economy of south Peru. By linking up the series of events inferred from Spanish chronicles with the lithofacies and composition of the tephra (bulk volume 11.4–12.1 km3, dense rock equivalent (DRE) 4.6–4.95 km3), we distinguish five eruptive phases. […] The geochemical and mineralogical trend throughout the eruption, and preliminary measurements of geobarometers suggest a complex model linking a shallow (6–7 km) magma reservoir to a deeper (∼15 km) reservoir. The total DRE volume (4.6–4.95 km3) of erupted tephra did not lead to caldera collapse. Ring fractures cutting multiple vents are associated with a dyke swarm intruding the weathered volcanic bedrock. This suggests the onset of a funnel-type or piecemeal collapse.