- Soufrière Hills Volcano shows measurable increase in level of unrest
The Montserrat Volcano Observatory reports that activity at the Soufrière Hills Volcano has remained low but has shown measurable increase in the level of unrest in the last year. In particular, the volcano has produced higher rates of volcano-tectonic earthquakes since around 2019, and these have further increased in number over the last 12 months.
Monitoring of ground deformation indicates a slow but continuous inflation over the island. This established long-term trend of inflation is consistent with that observed over the previous 13 years. Measured SO2 fluxes have averaged ~300 tonnes per day over the last 6 months, a decrease from the previous year but still slightly above the long-term average. Thermal camera images of fumaroles on the dome were last acquired in March and indicate maximum temperature of 522 ℃ which is consistent with the increased temperatures observed since 2018.
Overall, the unrest for the past 12 months is the highest observed during the current pause. However, based on previous restarts, we would expect a further increase in unrest prior to the resumption of any significant eruptive activity. The best explanation for this unrest is pressurisation of the magmatic reservoir at depth, possibly driven by a continued supply of magma and gas.
The volcano, with its large lava dome, is still a potential source of hazards within Zone V, including explosions, pyroclastic flows and lahars. Resumption of lava extrusion, or explosions, is still possible, however, the chance that explosions or pyroclastic flows will occur within the next year remains low. Continuous monitoring of the volcano is essential.
