IDEAN   23403
INSTITUTO DE ESTUDIOS ANDINOS "DON PABLO GROEBER"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
PRE-ERUPTIVE GEOCHEMICAL CHANGES OF THE PETEROA VOLCANIC GASES AS PRECURSOR OF THE 2018-2019 ERUPTION
Autor/es:
LAMBERTI, M.C.; CARBAJAL, F.; BUCAREY, C.; NUÑEZ, N.; AGUSTO, M.; TASSI, F.; GARCÍA, S.; BOBROWSKI, N.; SÁNCHEZ, H.; NOGUES, VICTORIA; LLANO, J.; VELASQUEZ, G.; KUHN, J.; GÓMEZ, M.
Lugar:
Estocolmo
Reunión:
Workshop; 1° Virtual Commission on the Chemistry of Volcanic Gases; 2021
Resumen:
Peteroa volcano (35.240oS, 70.570oW, 3603 m.a.s.l.) is part of the NNE-orientedPlanchón-Peteroa-Azufre Volcanic Complex (Argentina-Chile), located at theSouthern Andean Volcanic Zone. Peteroa volcano is characterized by frequentphreatic and phreatomagmatic eruptions. After the 2010-2011 eruptive period, thevolcano showed low degassing and seismicity activities. However, since 2017 anincrease in seismic activity was observed, followed, since 2018, by increasing in gasemission from the crater area, which culminated on December 14th, 2018, when anew phreatomagmatic eruption occurred. In this study, the chemical and isotopiccompositions of gases from crater emissions measured and collected between 2015and 2018, prior and during the ongoing volcanic crisis from Peteroa volcano arepresented and discussed. During the pre-eruptive period (2015-2018), the fumarolesfrom the summit crater showed a significant increase of the SO2/CO2 and SO2/H2Sratios, from 1.5x10-4 and 5x10-3 recorded in 2016-2017, to 4x10-2 and 4x10-1,respectively. During February-March 2018, a SO2 flux of 188(±28) tSO2/d wasmeasured by DOAS, while the CO2/SO2 ratio of the plume, determined by PITSA,ranged from 1,44 to 1,81, providing an estimated CO2 flux of 300(±72) tCO2/d. Theobserved changes in fumarolic gas composition and the increased degassing activityoccurred in 2015-2018 suggest an input of fluids from magma as precursor of the2018-2019 eruption.