Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 19 February
to 16:00 20 February 1997
The current alert level is AMBER

Activity at the volcano was slightly higher during the past 24 hours although overall, the activity level is still low. A swarm of earthquakes was experienced early today. Low cloud cover over the volcano prevented any clear views of the summit.

Seismic activity has been dominated by a swarm of earthquakes which occurred between 1:20 and 7:52 am today. The swarm was preceded by a period of tremor on the Gages seismic station which began at a few minutes past midnight. The earthquake swarm began with a period of irregularly spaced volcano-tectonic and hybrid earthquake which continued up to about 3:30 am. This was followed by a period of regularly spaced hybrid events which attained a maximum frequency of about one event per minute. The remainder of the reporting period was relatively quiet with only a few small rockfalls recorded. A total of 104 hybrids, 62 volcano-tectonic earthquakes and 15 rockfalls were recorded during the reporting period.

Visibility was generally poor for most of the day with only the lower flank of the volcano being visible at any time. Rockfall activity during the early morning earthquake swarm produced small ash clouds which drifted towards the west depositing light ash in these areas.

No EDM or GPS measurements were made today.

The dome is currently larger than ever before, and 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 and responsible at all times, carry ash masks and spend the minimum possible time in the evacuated zone. It is advisable to have access to a battery operated radio in case of electricity power cuts. Ash levels in Plymouth are hazardous, especially during dry, windy weather, and so it is essential to wear masks in areas affected by ash. Flash floods could cut off access to areas south of Fort Ghaut; visitors should leave that area when it rains. The Tar River Valley and the upper Galway's area are very dangerous and should not be entered at any time.

Montserrat Volcano Observatory