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Montserrat Scientific Advisory Committee hints at ‘beginning of the end’ of the eruption 13 September 2009

Posted by admin in activity reports, Caribbean, Soufrière Hills, volcano monitoring.
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The Montserrat Volcano Scientific Advisory Committee (SAC) is a group of expert volcanologists who have long associations with Soufrière Hills volcano, who meet at intervals to assess the development of the ongoing eruption on the island. SAC findings are passed on to the relevant scientific and administrative authorities, and public meetings are held to keep the Montserrat population informed. Some of the issues raised by this rather complex and indirect method of monitoring the eruption are discussed in an interesting article by an independent Montserrat-watcher: ‘Who trusts who, and why?’

The SAC have just held their 13th meeting in Montserrat and are currently putting together their full report. In the meantime, we have a preliminary report from them which recounts that Soufrière Hills ‘has had a quiet six months since our last report’ with ‘no extrusion of new lava and no explosions’, and that there is ‘no evidence from either seismicity or visual observations that the dome was recently intruded or strained internally such that its stability has changed’. The monitoring network has been re-instated and upgraded on the volcano, improving the data available to the scientists and the authorities. Their assessment of this information suggests that the behaviour of the volcano is changing, and one possibility is that perhaps the eruption could be running down at last:

These sets of measurements show that the volcanic system remains active. However, the number of earthquakes recorded has fallen to the lowest level we have seen during the eruption. This, together with the pattern of shorter duration extrusion events seen in the last 18 months, suggests that the long-term behaviour may have changed. One interpretation of this is that it hints at a possible ‘beginning of the end’ of the eruption, though all the formal end-of-eruption criteria are not yet met.

Time will tell. For the moment, the SAC report ends with the warning that the risks presented by the volcano to those living closest to it have changed very little, and that ‘sudden resumption of explosive and extrusive activity can rapidly pose a threat’ to adjacent zones.

News
The Scientific Advisory Committee releases Preliminary Statement – Government of Montserrat, 11 September 2009
SAC 13 Preliminary Statement – Montserrat Volcano Observatory, 11 September 2009
Montserrat Volcano’s Scientific Advisory Report – Possible ‘Beginning of the End’ of Eruption – Caribbean Press Releases, 12 September 2009

Information
Global Volcanism Program: Soufrière Hills – information about Soufrière Hills volcano (1600-05=)
Montserrat Volcano Observatory – detailed and up-to-date information from the MVO

The Volcanism Blog

Comments

1. Rusty Mason - 13 September 2009

The SAC in my mind did not hint at the end of the eruption. They merely mentioned it as one possibility given the fact that seismicity has been low and not a huge amount has happened in the last six months. It is by no means the most likely possibility!

There have been several long pauses over the past 14 years of this eruption…

2. Michael Finn - 13 September 2009

The SAC’s exact words are there in the post, and it seems to me that they are indeed hinting at the ‘beginning of the end’ of the eruption. They go out of their way to identify it as a possibility: I don’t think it’s unreasonable to describe that as a ‘hint’.

It’s made clear in this post that the SAC are not saying that *is* going to happen, or even that it is the most likely outcome. I don’t think it is, either, but we won’t know until time passes and the volcano either continues quiescent or fires up again, in which case we can write this one off as one more pause.

3. admin - 13 September 2009

Thanks for your comments, Rusty and Michael. Actually I do agree with Rusty that the post title is a bit strong and gives a slightly misleading impression, but I don’t know if it’s worth the trouble of changing it.


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