Montserrat Volcano Observatory
Report for the period 29 August to 5 September 2008
Activity at the Soufriere Hills Volcano this week has been at a low level consisting mainly of continued rockfalls and mudflows. Although the lava dome has been obscured by cloud, all evidence suggests that slow lava extrusion continues on the western side of the dome.
Mudflow signals were recorded on 29 and 31 August and on 1 September. The mudflows on 29 and 31 August began at 4 and 11pm respectively and most likely occurred in the Tar River Valley. The flow on 1 September was the most significant. It occurred in the Belham River Valley, began at 7:30am and lasted for approximately 50 minutes.
The lava dome was obscured by cloud for most of the week; however conditions cleared sufficiently on Thursday 4 September to allow observations to be made from the helicopter. The dome remains essentially the same with the rockfall gully developed over the Gages valley on the western side of the dome being the main focus of activity on the dome. One new feature observed was a vent on the north-western part of the dome. This new vent is at approximately the same height as the previous Gages vent but a bit further north.
North and north easterly winds for most of the week blew the gas plume over inhabited areas of Montserrat and the smell of volcanic gases was very noticeable at times.
Seismic activity continues at a low level. MVO recorded 16 rockfalls, 6 long period, 11 hybrid and 6 volcano-tectonic events this week. Most of the rockfalls were on the western side of the dome in the steepened the rockfall gully over the Gages Wall.
Reliable measurements of the sulphur dioxide (SO2) flux were not possible for the entire week because the wind direction kept the plume outside of the monitoring network.
Lava extrusion is expected to continue. Visual observations along with the monitoring signals suggest that the extrusion rate is relatively low, but an increase cannot be ruled out. Pyroclastic flows may occur without any warning, especially when there is heavy rainfall.
The Hazard Level is 3.
Additional information on the Soufrière Hills Volcano and the new Hazard Level System can be found at the MVO website: http://www.mvo.ms.
Dr Richard Robertson
Director
Montserrat Volcano Observatory
PO Box 318
Flemmings
Montserrat W.I.
Tel: 1-664-491-5647
Fax:1-664-491-2423
Email: richie@mvo.ms
Web: http://www.mvo.ms
