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Welcome to montserratvolcano.org
This website is neither created nor owned by the residents of Montserrat but I hope that they will treat it as their property and help me develop it in whatever way they wish. Montserrat has been greatly troubled and partly laid waste by an erupting volcano for more than a decade. This was peaceful (apart from occasional relatively small explosions) from early 2007 until just before the date when I was planning to publish the website (29 July 2008). During the previous night major new eruptive activity took place and the circumstances surrounding this are detailed on the MVO website, together with photos of both the 28 July deposits and their Gages Vent source, at http://www.flickr.com/photos/mvo/. Since then lava extrusion started, stopped and started again at Gages Vent. In addition, another vent opened on the NW side of the lava dome in early September 2008 and this produced some violent explosions (without any warning) on 3 January 2009. Subsequently, the eruption paused again and the report of the 12th meeting of the international Scientific Advisory Committee (SAC) at MVO in March 2009 suggested that further short (few weeks) periods of lava extrusion and sudden explosions might occur during the coming year. As the main extrusion vent had moved in December 2008 towards its "traditional" site atop the dome, the SAC considered that the risk had increased slightly of a future major dome collapse and/or explosion sending pyroclastic flows (PFs) into the Upper Belham Valley (via Tyer's Ghaut) and thus continuing to enlarge and smooth the growing debris fan there. Such debris fans make it easier for future PFs perhaps to reach the Lower Belham Valley -- a process seen earlier in the eruption, during the burial of Plymouth by PFs.
The volcano was clearly listening intently to the SAC in March 2009 and has since done precisely what they forecast! It remained peaceful through the summer and allowed Montserratians to concentrate on the excitement and outcome of a General Election in September. Then it re-awakened abruptly on 4 October, after giving only about three days of warnings (increased earthquake numbers and an abrupt drop in the amounts of SO2 emitted from the volcano). Explosions between 4 and 7 October sent ash plumes up to about 6000 metres. By 9 October a new lava dome could be seen growing on the summit of the previous one (the one that has failed to collapse wholesale since it formed in 2006-7, despite earlier “near certain” forecasts that it would do so). Between early October 2009 and mid-February 2010 the volcano really showed its teeth. Rapid lava extrusion increased both the height and volume of the dome to the largest yet seen. Several very large explosions, with little or no obvious warning, sent PFs into new places, such as the seaward ends of Aymers and Gingoes Ghauts. On 10 December a PF reached to below the western end of Lees village and triggered an NDPRAC decision to evacuate Zone B (see MVO website for the acronyms etc). On 8 January a PF generated by another very large and unannounced explosion travelled about 6 km down the Belham Valley – further than ever before during the long eruption and reaching to within about 500 m (as flown by a terrified chicken!) of houses occupied until shortly before the evacuation.
After very rapid further growth in early February, about 20% of the dome collapsed (accompanied by huge explosions), feeding about 40-50 m3 of material ranging from fine ash to house-sized blocks in to a series of PFs that inundated the entire NE slopes of the volcano. Some of the PF material also came down the Belham Valley, to the NW, and stopped only about 1 km away from the evacuated areas. Since then the volcano has reverted rapidly to its quiet-as-a-mouse behaviour and the residents have returned to their extremely dusty homes around the Lower Belham Valley. But for how long?
There is of course an excellent and comprehensive, recently redesigned, official Montserrat Volcano Observatory (MVO) website [http://www.mvo.ms/] and you may think; “Why another one?” Just take a quick look at this one and decide for yourself if it is helpful to you. Whatever you decide, please let me know. This website is designed to be read with Wikipedia [http://en.wikipedia.org/wiki/Main_Page] open at the same time on your computer. Whenever you find a word or phrase that needs more explanation, just type it into the search line of Wikipedia and read more about it there. For those of you who would like to see an overall account of the eruption at a more detailed and "scientific" level than this site, but less than MVO or the research literature, try Richard Roscoe.
I start with a short account of the most obvious thing – why is there a volcano on Montserrat? Most of you “know” the answer to this question but are split between two entirely different viewpoints. For some, it is part of God’s creation and that’s all there is to it. Others prefer the explanations worked out by scientists and this is the approach that I shall take here. Nevertheless, it’s essential to say at the outset that only this first theme will be seen differently by different residents. The following themes will be designed to be equally useful to all of you, by discussing practical matters about the eruption and its threats. Even strongly religious people may find that the following material about volcanic magma and lava domes is interesting.
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Soufrière Hills from Jack Boy Hill (2007) Bob Thompson |
Soufrière Hills from St George's Hill (2007) Steph Flude |
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CONTENTS
1. General introduction: the science view, page 1. edited 12 APRIL 2010
page 2. expanded 9 APRIL 2010
2. Introduction to pyroclastic flows and surges, page 1. expanded 13 APRIL 2010
page 2. expanded 13 APRIL 2010
page 3. expanded 14 APRIL 2010
3. Mathematical modelling of pyroclastic flows: the E' VIVO! website.
4. Blast, heat, debris and dust: how do pyroclastic surges damage buildings? page 1. edited 15 APRIL 2010
page 2. edited 15 APRIL 2010
page 3. edited 15 APRIL 2010
5. Blast, burns, asphyxia and hypoxia: how do pyroclastic surges damage humans?
6. How pyroclastic surges sometimes “bounce” landwards when they reach the sea. expanded 16 APRIL 2010
7. A surge’s dangerous offspring: secondary pyroclastic flows. edited 15 APRIL 2010
8. Say no to maps? How to communicate volcanic hazard effectively on Montserrat, page 1. edited 17 APRIL 2010
page 2. expanded 17 APRIL 2010
9. Who trusts who and why? Risk communication during the Montserrat volcanic eruption, page 1. edited 17 APRIL 2010
page 2. edited 17 APRIL 2010
page 2. updated 21 JUNE 2010
11. Montserrat at war: living beside a dangerous volcano. ADDED 29 APRIL 2010
12. Can geophysical modelling predict the end of the Soufrière eruption?
13. Comments and discussions. If you wish to make a point, please email me at bobnthompson@gmail.com and I'll answer and also put it on a discussion page for you, if you wish.
14. Notes from a very small island for would-be visitors expanded 2 MAY 2010
15. Where next for Montserrat? page 1. ADDED 9 JUNE 2010
page 2. ADDED 9 JUNE 2010
16. Housekeeping.
Last updated 14 August 2010
