MVO report for the period May 2 to May 9, 2008
By MVO
Fri, 9 May 2008, 16:01
Montserrat Volcano Observatory
Report for the period 2 May to 9 May, 2008
The pause in dome growth at the Soufriere Hills Volcano continues. Measurable activity remains low although there was a small pyroclastic flow on the eastern flank of the volcano at 2 am on Monday 5th May. Light ashfall was reported in the Old Town area and fresh ash was evident in the Corkhill and St Georges Hill areas for several days afterwards. The flow may have been triggered by very heavy rainfall at the time, which also generated lahars.
The volcano-tectonic earthquake activity recorded at the end of April stopped on 2nd of May. This week, the seismic network recorded five rockfalls, five long-period events and ten volcano-tectonic earthquakes. Eight of the ten volcano-tectonic earthquakes were associated with the pyroclastic flow on 5th May and were located at very shallow depths in the vicinity of the dome.
The average sulphur dioxide flux for the week was 630 tons per day, with daily values ranging from 523 to 946.
Although there is currently no lava extrusion, the dome is still a very large mass of very hot material which is capable of collapsing or exploding at any time. Lahar activity in river valleys around the volcano is a potential hazard during and after periods of heavy rainfall.
The alert level remains at 4.
Access to all areas on the southern flanks of the Belham Valley except Isles Bay Hill and the east of the Belham Bridge, is prohibited as is south of Jack Boy Hill to Bramble airport and beyond. The Maritime Exclusion Zone around the southern part of the island extends 4 km off shore from Spanish Point to Roches Yard on the east side of the volcano, 2 km offshore from O’Garras to Sturge Park on the south west.
Additional information on the Soufrière Hills Volcano, including the risk map, can be found at the MVO website: http://www.mvo.ms.
Roderick Stewart
Acting Director
Montserrat Volcano Observatory
Flemmings
Salem
Montserrat
Tel: 1-664-491-5647
FAX: 1-664-491-2423
e-mail: rod@mvo.ms; mhst@bgs.ac.uk