Professional background in volcanic gas monitoring. Experience in direct sampling and analytical determination of gases from fumaroles and geothermal wells, application of gas geothermometers, and determination of diffuse soil CO2 fluxes and concentrations in volcanic areas. Growing skills in physical models for the dispersion of volcanic ash and gas and hazard assessment.
EDUCATION
Bachelor's degree in Geology
Master's degree in Environmental Geology, Geological Risks and Land Management
Bachelor's degree in Chemistry
RESEARCH, TEACHING, or OTHER INTERESTS
Earth and Planetary Sciences
2
Scopus Publications
Scopus Publications
Monitoring hydrothermal fumaroles in the Azores archipelago - Applications and sources of analytical uncertainties D. Matias, M. Antlauf, F. Viveiros, L. Moreno, C. Silva, S. Oliveira Journal of Volcanology and Geothermal Research, 2024 The Azores archipelago is located in the North Atlantic Ocean and is formed by nine volcanic islands. Present-day volcanic activity in the archipelago comprises not only seismic swarms and episodes of ground deformation in some volcanoes, but also hydrothermal gas manifestations. The main fumaroles are associated with central quiescent volcanoes and have been sampled in the past decade through the Giggenbach methodology. Analysis of the fumarolic fluids from four volcanic systems in São Miguel, Terceira, and Graciosa islands are displayed for the period between July 2015 and February 2023. No significant changes have been observed both on the selected gas ratios (CO2/CH4, H2/CH4, He/CH4, He/CO2, and H2/Ar), and on the equilibrium temperatures estimated for the reservoirs feeding the fumaroles using the H2/Ar gas geothermometer, what is in agreement with the dormant state of activity of the studied volcanic systems. Equilibrium temperatures ranging between 223 °C and 262 °C are estimated for Fogo and Furnas fumarolic fields (São Miguel Island), and an average equilibrium temperature of 254 °C is inferred for Terceira fumaroles. This study also suggests a procedure based on established guidelines to evaluate the analytical uncertainties of the methodologies associated with the Giggenbach sampling strategy. Comparison of the analytical uncertainties with the overall data variation (including additional natural variations and sampling uncertainty), shows that the analytical uncertainties are not the limiting factor for the interpretation of the survey results.
The contribution of hydrothermal mineral alteration analysis and gas geothermometry for understanding high-temperature geothermal fields – The case of Ribeira Grande geothermal field, Azores M.L. Pereira, D. Matias, F. Viveiros, L. Moreno, C. Silva, V. Zanon, J. Uchôa Geothermics, 2022 The Ribeira Grande geothermal field is located on the northern flank of Fogo Volcano (S. Miguel Island, Azores) and it is characterised by the presence of several active hydrothermal manifestations. An analysis of the RG5 geothermal well has been carried out by the recognition of neoformation minerals with depth and the estimation of equilibrium temperatures. The formation of hydrothermal minerals depends not only on temperature but also on subsurface geology. The mineral assemblage consisting of chlorite + quartz + haematite ± calcite ± anatase ± titanite + albite ± adularia (± dolomite) shows temperature above 235 °C, and the main alteration is divided into a smectite zone followed by a chlorite zone at depth. The adularia appearance evidences a boiling zone at the top of the reservoir and illite and chlorite also suggest fluid level fluctuations in the past. The H2/Ar gas geothermometry applied to the gases emitted by fumaroles points to a temperature of 256 °C for the reservoir feeding a fumarolic field located close to the RG5, which sustains the mineralogical research.
