Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 14 March
to 16:00 15 March 1997
The current alert level is AMBER

Activity at the volcano has been lower today with the end of the shallow earthquake swarm that started yesterday morning. Visibility today has been variable and occasional good views of the dome were possible, showing that dome growth appears to be slow.

Seismic activity at the volcano has been dominated by a swarm of volcano-tectonic and hybrid earthquakes. The swarm began early yesterday morning and continued until 9.03 pm last night. A total of 45 hybrids and 6 volcano-tectonic events were recorded during this reporting period. Rockfall activity has been at about the same level with only 5 events recorded. In addition there was a regional earthquake today at 2.57 pm. This was located to the south-east of Montserrat.

Visual observations have been hampered by variable low cloud around the volcano. Some good views of the eastern side of the dome complex were obtained this morning and later this afternoon. Minor rockfall activity from the east and south-east of the dome was observed from Whites, Harris and Long Ground. Overall it appears that visible growth of the dome complex is still slow. However a new small spine on the top west side of the January dome was visible from Farrells and Windy Hill.

A GPS survey on the network to the east of the volcano was completed today. The data will be processed later today or tomorrow.

COSPEC measurements were carried out this morning along the road to the west of the volcano. The data are currently been processed and will be available for a future report. Results from yesterday show a decrease in the average sulphur dioxide flux to 213 t/d.

During the last few days the eastern slope of the dome continues to be unstable. Given that the dome is now large and continuing to grow, albeit slowly at the moment, a large collapse and pyroclastic flows could happen with little warning. The increase in activity from the Galway's Wall makes this area particularly hazardous, especially if there is a recurrence of the earthquake swarms. It is dangerous to spend the night in evacuated areas, because the situation could worsen rapidly over a period of a few hours. People entering Zone C are reminded to remain alert at all times, and spend the minimum possible time in the evacuated zone. The Tar River Valley and the upper Galway's area are very dangerous and should not be entered at any time.

Montserrat Volcano Observatory