Montserrat: MVO report for the period midday 27 Apr to midday 04 May 2007

Visual observations revealed very little change to the overall dome structure during the period, although fresh deposits are present in the head of Tyres Ghaut, the upper parts of Farrell's Plain and the Tuitt's Ghaut and the upper parts of the Tar River. Pyroclastic activity has been ongoing on the east and northeastern sides of the dome, and flows have been observed in the Tar River Valley and on Farrell's plain running out into Tuitt's Ghaut. As the dome stands, a significant proportion of the dome material remains in the sector above Tyres Ghaut to the northwest. The amount of material here is sufficient to generate pyroclastic flows and surges capable of impacting on the lower Belham Valley.

Recorded seismic activity has remained very low throughout the period. The seismic network recorded 9 rockfall signals.

The sulphur dioxide (SO2) flux rate during the reporting period was low, ranging between a minimum of 125 tones per day (t/d) to a maximum of 320 t/d. The average of 223 t/d is comparable with emission levels recorded the period January to March 2007, and below the longterm average for the eruption (550 t/d).

The alert level remains at 4.

Residents of Montserrat and visitors to the island are advised to tune into ZJB Radio 88.3 or 95.5 FM for up-to-date information on the volcano.

Access to all areas on the lower flanks of the Belham Valley and further south, and south of Jack Boy Hill to Bramble airport and beyond is prohibited at all times (readers are refereed to the updated risk map). 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, and 2 km offshore from Isles Bay to Old Road Bluff on the west (maritime risk map).

For further explanations of the volcanic phenomena described, and information about the Soufrière Hills Volcano and the ongoing eruption, please look at the rest of the MVO website.