Reconstruction and aftermath of the catastrophic AD 1600 Huaynaputina eruption, south Peru
by
Jersy Marino
Instituto Geofisico del Peru
Coauthors: J.C. Thouret (Laboratoire de géomorphologie, Université d'Etat à Liège, Liège, B 4000 Belgique), J. Dávila (Instituto Geofisico del Peru, Lima, Peru), E. Juvigné (Université d'Etat à Liège, Liège, Belgique), M. Moscol, Universidad Agraria, Lima, Peru)

The largest historical eruption in the Andes occurred on February 19-March 6-15, A.D. 1600 at Huaynaputina in south Peru. By linking up the events inferred from Spanish chronicles with the lithofacies of the tephra, we distinguish five eruptive phases.

(1) During the plinian phase on February 19-20, a sustained column delivered a dacitic pumice-fall of ~7 km3 bulk volume. The plinian pumice formed a widespread lobe of ~95,000 km2 within the 1-cm isopach and winds carried fine ash >500 km to the west into the Pacific Ocean. (2) During the second phase, a dwindling column sent ash falls on proximal to medial areas. (3) During the third ignimbrite-forming phase with interspersed hydromagmatic events, pyroclastic flows 1.5-2 km3 in volume were channeled into the Río Tambo canyon and tributaries. Winds winnowing the ash columns over high, rugged relief dispersed a co-ignimbrite ash over an area of ~ 265,000 km2. (4) During the fourth phase, a crystal ash fall was deposited when the residual crystal-rich magma was tapped near the end of the eruption. (5) During the fifth phase, ash flows produced surge deposits and lag-fall breccias near vent, ash-flow deposits in proximal catchments, and an ash fall layer in medial to distal areas. The total bulk volume (ca.12 km3) of erupted tephra did not lead to caldera collapse.

The aftermath of the eruption was severe and protracted on the people and colonial economy of south Peru. Voluminous lahars swept the Río Tambo valley and entered the Pacific Ocean. Approximately 1500 people were killed, villages were buried, and the town of Arequipa 75 km away suffered havoc from ash fall and earthquakes. The economic ruin was due to the total loss of crops, cattle, and seeds, and to interrupted trade for years. Epidemics, famine, and poverty were added to the general ruin.

Date received: February 28, 2002

Copyright © 2002 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # caiq-31.