资源环境科技发展态势分析平台

Springs at La Soufriere of Guadeloupe have been monitored for nearly four decades since the phreatic eruption and associated seismic activity in 1976. We conceptualize degassing vapor/ gas mixtures as square-wave sources of chloride and heat and apply a new semianalytic solution to demonstrate that chloride and heat pulses with the same timing and duration result in good matches between measured and simulated spring temperatures and concentrations. While the concentration of chloride pulses is variable, the local boiling temperature of 96 degrees C was assigned to all thermal pulses. Because chloride is a conservative tracer, chloride breakthrough is only affected by one-dimensional advection and dispersion. The thermal tracer is damped and lagged relative to chloride due to conductive heat exchange with the overlying and underlying strata. Joint analysis of temperature and chloride allows estimation of the onset and duration of degassing pulses, refining the chronology of recent magmatic intrusion.

Plain Language Summary Between eruptions, volcanoes continue to produce gases and water vapor associated with the cooling of magma (molten rock) deep beneath the volcano. These deep processes discharge gas and vapor (fumaroles) and heat the groundwater flowing through the volcano. Volcanic gases and vapors also contribute chemicals to the groundwater. Where groundwater leaves the volcano at springs, temperature and chemical measurements can be used to better understand the history of magmatic activity beneath the volcano. Understanding the history of volcanic processes aids volcanologists (scientists who study volcanoes) in understanding what conditions precede violent eruptions that might result in catastrophe.