Measuring and interpreting heat fluxes from shallow volcanic bodies using vertical temperature profiles: a preliminary test

Abstract

To test the potential of heat flux prospecting in active volcanic areas using shallow temperature data taken along vertical profiles, we carried out two thermal profile surveys, one not far from Yasur cone on Tanna Island, and another inside the caldera of Ambrym (New Hebrides arc, southwestern Pacific). The basic steady heat flux of internal volcanic origin was determined, taking into account both conductive and convective heat transfers. At both locations there exists, over small distances, significant differences in the heat flux. These differences correspond to shallow sources of heat. The use of a network of vertical profiles allowed: (a) heat flux mapping; (b) location of shallow volcanic heat sources; and (c) observation of the detailed structure of the heat release at quiescent but active volcanoes.