Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 24 February
to 16:00 25 February 1997
The current alert level is AMBER

The level of activity at the volcano has been low over the last 24 hours. An earthquake swarm last night was followed by low level rockfall activity today. Visibility has been poor throughout the day and no good views of the dome have been obtained.

The seismic activity during this reporting period was dominated by an earthquake swarm between 5.57 pm last night and 2.00 am this morning. In total, 60 volcano-tectonic and 32 hybrid earthquakes were recorded, most of which occurred within this swarm. The volcano-tectonic earthquakes were located at depths of 1 to 4 km below the crater. Seven rockfall signals were also recorded by the seismic network. In addition, low amplitude tremor was recorded at Gages seismic station from 1.00 am this morning and is still continuing at the end of the reporting period. There were small peaks in the tremor at approximately 2.00 am and 1.00 pm.

Visibility was poor for most of the day but, at 3.41 pm, observers at Bramble airport reported a small pyroclastic flow to the base of the talus slope below the dome. There was also a lot of steaming from the summit of the volcano during the later part of the morning, and early afternoon.

COSPEC measurements of the sulphur dioxide flux from the volcano were made today for the first time since 7 February. The data are currently being processed and should be reported later this week. NO EDM or GPS measurements were made today.

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. Visitors to zone C are reminded to remain alert at all times, and spend the minimum possible time in the evacuated zone. 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