Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 25 February
to 16:00 26 February 1997
The current alert level is AMBER

Activity at the volcano has continued at a low over the last 24 hours. Another earthquake swarm occurred today. Visibility has been poor throughout the day and no good views of the dome have been obtained.

The seismic activity at the volcano was dominated by a swarm of volcano-tectonic and hybrid earthquakes between 8:30 am and 2:07 pm today. This swarm was less intense than the one which ended early yesterday morning. A total of 34 volcano-tectonic and 17 hybrids were recorded during the reporting period, most of these occurred during the swarm. The volcano-tectonic events were located at depths of 1 to 4 km below the crater. Eight small to moderate sized rockfall signals were also recorded by the seismic network. One regional event was also recorded by the seismic network.

The period of low amplitude tremor which began on the Gages station at 1:00 am on 25 February continued during the reporting period. The tremor intensified from about 8:00 pm to 11:00 pm last night and became visible on most stations close to the volcano. After this period the level decreased and had returned to background by 2:30 am today.

Low level cloud over the volcano prevented any views of the summit today. However, a few small rockfalls were observed from the dome by the scientists doing field work at Whites.

The results of COSPEC measurements made yesterday indicate a sulphur dioxide flux of 217 tons per day. A GPS survey of the MVO EASTNET, which includes stations located on the eastern flank of the volcano, was completed today. The results from this survey is not yet available. NO EDM measurements were made today.

The volcano remains active and potentially dangerous. The dome is currently larger than ever before, and so further dome collapses and pyroclastic flows are expected. These will probably follow the recent pattern, but a change in the activity could occur at any time. People entering Zone C are reminded to remain alert at all times, and spend the minimum possible time in the evacuated zone. The ash levels in Plymouth are hazardous, especially during dry, windy weather, and so it is essential to wear masks in areas affected by ash. The Tar River Valley and the upper Galway's area are very dangerous and should not be entered at any time.

Montserrat Volcano Observatory