Castruccio, A. J. Clavero & A. Rivera. (2010) : “Comparative study of lahars generated by the 1961 and 1971 eruptions of Calbuco and Villarrica volcanoes, Southern Andes of Chile” Journal of Volcanology and Geothermal Research, doi: 10.1016/j.jvolgeores.2009.12.005.

Resumen / Abstract.

The Villarrica and Calbuco volcanoes, of the Andean Southern Volcanic Zone, are two of the most active volcanoes in Chile and have erupted several times in the XX century. The 1961 eruption at Calbuco volcano generated lahars on the North, East and Southern flanks, while the 1971 eruption at Villarrica volcano generated lahars in almost all the drainages towards the north, west and south of the volcano. The deposit sfrom these eruptions in the Voipir and Chaillupén River (Villarrica) and the Tepú River (Calbuco) are studied.The 1971 lahar deposits on Villarrica volcano show a great number of internal structures such as lamination,lenses, grading of larger clasts and a great abundance of large floating blocks on top of the deposits. Thegranulometry can be unimodal or bimodal with less than 5% by weight of silt+clay material. SEM image sreveal a great variety of forms and compositions of clasts. The 1961 lahar deposits on Calbuco volcano have ascarce number of internal structures, steeper margins and features of hot emplacement such as semi carbonized vegetal rests, segregation pipes and a more consolidated matrix. 

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