Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 21 February
to 16:00 22 February 1997
The current alert level is AMBER

The level of activity at the volcano has remained the same, with a continuation of earthquake swarms. Overcast conditions did not allow any views of the dome.

Seismic activity has been dominated by another swarm of earthquakes with a total of 85 hybrid and 84 volcano-tectonic earthquakes recorded. The swarm extended from 1:03 to 7:57 am today and was similar to earlier swarms, with volcano-tectonic earthquakes followed by repetitive hybrid earthquakes. The interval between swarms is now about 16 hours with the swarm duration varying from 7 to 8 hours. Today's swarm was slightly less intense than the swarms yesterday but at it's maximum, the hybrid earthquakes occurred at a rate of one per minute. A period of low-amplitude, continuous tremor began at 11:30 am today and is still ongoing. Otherwise, the level of seismic activity was low, with only 10 rockfalls and one long-period earthquake recorded. As usual, the earthquakes were too small to be felt.

Visibility was generally poor for most of the day and no clear views were obtained of the volcano.

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 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. 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