Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 28 March
to 16:00 29 March 1997
The current alert level is AMBER

Volcanic activity has continued at a similar level to yesterday. There have been few earthquakes, but several rockfalls and some pyroclastic flows over the Galway's Wall.

A total of 1 volcano-tectonic, 2 hybrid and 12 long-period earthquakes were recorded. This is an increase on the number of long-period events compared to yesterday. There were 10 rockfall signals. The largest signal was at 16:30, just outside the reporting period. This was caused by probably the largest pyroclastic flow over the Galway's Wall to date. This produced a moderate sized ash cloud. The rapidly convecting nature of the ash cloud generated by the pyroclastic flow suggests that hotter material is now being shed from the January dome over the crater wall. The dark grey colour of the ash cloud compared to earlier pale grey clouds further support the idea that hotter material is now involved.

Observations were made today from the helicopter in clear conditions. The top of the dome is now made up of two separate peaks, the higher of the two overlooking the Galway's Wall. There is now no barrier from the pre-September dome in this area, explaining the involvement of hotter material in the pyroclastic flow at 16:30. The south and south-east side of the dome is very active and heat could be felt by the scientists in the helicopter. Little activity was observed on the north and north-east flanks. The flows into the area around the Galway's Soufriere have developed a chute and levees in the lower parts.

No EDM or GPS surveys were carried out today. No further COSPEC measurements are currently available.

The dome is now very big and still growing, and a dome collapse with large pyroclastic flows could happen with little warning. 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