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Integration of satellite and ground-based thermal sensor surveys to constrain heat fluxes at hydrothermal systems: experiences from Poás and Nisyros

^^Sophie Pailot-Bonnétat^1^, Andrew Harris1, Victoria Rafflin1,a, Céline Bonnetain1, Alessio Serravalli1, Loÿc Vanderklyusen2, Jacob Brauner2, Christina Liu2, Michael Ramsey3

  • Affiliations: 1 Laboratoire Magmas et Volcans, Université Clermont Auvergne, Clermont-Ferrand, France 2 Department of Biodiversity, Earth & Environmental Science, Drexel University, Philadelphia, U.S.A. 3 Department of Geology and Environmental Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, U.S.A 

  • Presentation type: Poster

  • Presentation time: Monday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 237

  • Programme No: 2.4.23

  • Theme 2 > Session 4

Abstract

a Now at Department of Earth Sciences, Royal Holloway, University of London, Egham, UK At active volcanic hydrothermal systems, enhanced heat flow results in surface heating and elevated heat flux densities. We consider heat transfer models for: (1) "dry" systems with soil heating and fumarolic activity, and (2) "wet" systems, i.e., a crater flooded with an acidic lake. Our aim is to collate and review methods to calculate heat flux, while assessing the role of external atmospheric processes. To do this, we completed thermal mapping and collected meteorological data in June 2022 at Nisyros (Greece) and in February 2002 at Poás (Costa Rica). Measurements coincided with a thermal infrared satellite sensor overpass. At both systems, the low magnitude of the thermal anomaly means that atmospheric factors, in particular vapor pressure, drive high degrees of variation in heat flux during a diurnal cycle. These variations overprint the volcanic heat flux component. To characterize heat fluxes at a hydrothermal system, it is best to integrate through a whole diurnal cycle. At Nisyros and Poás, agreement between ground and satellite-based values of heat flux gives us confidence in our calculations. Heat fluxes were relatively low, 34.2±9.1 MW and 51.7±10.5 MW respectively, revealing a baseline state of activity. Our intention is that heat flux calculation methodologies detailed and validated here can be used at other similar systems. The key is to adequately account for atmospheric parameters in the thermal boundary layer, i.e. within 10 cm of the surface. This allows robust and comparable heat flux inventories to be applied to better understand activity at hydrothermal systems.