The thermal properties of submarine rhyolite lavas from Havre volcano (Kermadec arc, Pacific Ocean)

The thermal properties of lavas are required for modelling volcanic and hydrothermal processes, yet are scarce for submarine lavas. Laboratory experiments, using the transient hot-strip method, are used to understand the role of porosity, glass content, and pore fluid type on the thermal properties of submarine lavas from Havre volcano. Thermal diffusivity and specific heat capacity do not change systematically with porosity; however, thermal conductivity decreases as porosity increases. The thermal conductivity of the submarine lavas is lower than for subaerial lavas with the same porosity, a consequence of their higher glass contents. We show that, using our data and effective medium models, the thermal properties of any lava can be estimated as long as their porosity, glass content, and void-filling fluid phase is known. This approach can be used to estimate properties for multiphase models for submarine eruption dynamics, hydrothermal system hydrology, cooling timescales, and heat flux calculations.