Hydrothermal eruptions at unstable crater lakes: Insights from the Boiling Lake, Dominica, Lesser Antilles

Abstract

Conceptual models exist describing possible mechanisms of the Boiling Lake drainage itself, little information exists to date regarding the trigger mechanisms related to the explosive events. Further, no estimation of the eruption processes and dynamics of these events has previously been attempted. To address this knowledge gap, we employ here a combined field- and laboratory-based approach in order to i) characterize the properties of the dominant lithologies from the crater walls at Boiling Lake, ii) determine how the ongoing alteration may affect their petrophysical properties (e.g., porosity and permeability), and iii) evaluate how water-saturated, unconsolidated wall rock materials behave when rapidly decompressed from a slightly elevated pressure and temperature conditions. Here, we propose that it is the petrophysical state of the materials involved (e.g. porosity, permeability and alteration-related strength) which controls the style and energy of these eruptions, as well as the potential for landslides from the crater walls.