A Preliminary Statement #21 dated November 11, 2016, from the Scientific Advisory Committee (SAC) on the Soufriere hills Volcano in Montserrat states as follows:
“Soufrière Hills volcano has shown no significant changes in its behaviour during the past year. Seismicity has remained at a very low level except for occasional short episodes of volcano-tectonic earthquakes. Temperatures of volcanic gases that escape through fractures and fumaroles have remained high. Monitoring of ground deformation indicates a slow but continuous lengthening trend over the island, with a maximum uplift of about one centimeter over the last year. These trends are consistent with the activity we have seen over the previous 5 years. Measurements of Sulphur dioxide emission rates were not possible in the past year, but the existence of a visible plume shows that degassing is ongoing.
Taking these observations together, we conclude that the volcano remains in a state of unrest. We consider the most likely cause of this unrest the slow but steady accumulation of magma in a deep reservoir below the volcano. While a restart of lava extrusion remains a possibility in the future, there are no signs that this is imminent.
The major part of the lava dome remains stable but continuing erosion has the potential to destabilize steep parts of the dome. The chance that pyroclastic flows will occur within the next year remains low. However, the volcano is still a potential source of hazards, some of which could occur at any time with little or no warning and could pose a threat to people working in or visiting Zone V.”
Following this statement the MVO Weekly Report for the Period 4 to 11 November 2016 opened almost as usual “Activity at the Soufrière Hills Volcano remains low.” But concludes almost the same thing speaking to “Pyroclastic flows can occur at any time without warning on any side of the volcano, including Gages from where they can travel rapidly into Plymouth.” There is the slight difference that the yearly assessment said, “The chance that pyroclastic flows will occur within the next year remains low.”
The usual warning regarding Zone V was evident in both statements
A ZJB report puts it this way: “The Scientific Advisory Committee or S.A.C met here this week to assess the state of the Soufriere Hills and concluded that the volcano is in a state of unrest.”
Professor Jurgen Neuberg of the school of Earth Sciences and Environment at the University of Leeds chaired S. A. C’s 21st review, said: “It’s clear that if there was a significant change in terms of the gassing dropping down or the defamation reducing. That would be the sign and really this pause is more than a pause, it’s actually coming to a different stage in the evolution of the volcano but that’s really not what we’re saying this pause is very, very similar to the previous pauses which were shown in between eruptive periods.”
In support, Dr. Eleonora Rivalta from the German Research Center for Geosciences offered, “The defamation is really one of the critical points because if we still see that there is still some deep inflation even if that doesn’t pose as any threat right now on a practical point of view. Still it means that the volcano is been recharged.”
