Hydrothermal eruptions at El Humazo, Domuyo geothermal field, Argentina: Insights into the eruptive dynamics and controls

D'ELIA, L.; PÁEZ, G. N.; HERNANDO, I. R.; PETRINOVIC, I. A.; LÓPEZ, L.; KÜRTEN, G.; VIGIANI, L.

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH

ELSEVIER SCIENCE BV

Año: 2020 vol. 393

0377-0273

Hydrothermal eruptions are explosive events driven by the sudden and violent vaporization of thewater present in many hot water geothermal fields worldwide. Over recent years, thermodynamical conditions of fluids and petrophisical-geomechanical features of host-rockswerementioned as responsible of thewide range of eruptive styles and deposits of hydrothermal eruptions. Nevertheless, geological and historical records show that PDC and fallout processes are underestimated as common processes linked to hydrothermal eruptions. This paper analyzes from a multi-disciplinary approach ?virtual outcrops modeling, sedimentology, petrographic and XDR studies, facies modeling, eye-witness source analysis, and stratigraphy? the pristine Holocene?historic hydrothermal eruptive record of El Humazo manifestation (Domuyo Geothermal Field, Patagonia, Argentina). Different eruptive scenarios are characterized by ballistic ejection, PDC and/or fallout mechanisms with discernible tefracomposition and granulometry, associated with both excavational and/or aggradational landforms. We show howdiverse eruptive dynamics are controlled by pre-eruptive internal and external factors, such as reservoir energy, depth of the explosion/fragmentation levels, physical properties and structural anisotropy of the host-rocks and eruptive centermigrations. Weconsider that this case studymay be useful not only for the application in the assessment of the volcanic hazard associated with the Domuyo geothermal field, but also contributes to the knowledge of the eruptive dynamics in other geothermal systems with similar characteristics.