Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 19 November
to 16:00 20 November 1996
The current alert level is AMBER

Activity at the volcano continued at a fairly low level during the past 24 hours. The only seismic activity has been the continuation of a moderate swarm of VT earthquakes.

There have been 41 VT earthquakes recorded by the seismic network today. All of these earthquakes were at shallow depths beneath the crater. The swarm started at 06:30 yesterday, and continued throughout the reporting period. The level of activity was low, with a maximum of three earthquakes per hour recorded this morning, and the swarm now seems to be dying out.

No other seismic signals triggered the event recording system today.

Visibility was poor for much of the day. The wind direction was from the south, causing cloud to form to the north and west of the volcano. This meant that although the dome complex was visible at times from the west, only limited views of the October 1 dome were possible. Some changes in the northern part of the new dome were seen, indicating that dome growth continues.

No EDM measurements were carried out today because of the poor visibility in the east. The wind direction made COSPEC measurements impossible.

A GPS survey has been completed around the volcano, including sites at Tar River and Whites. The results are now being processed.

The current volcano-tectonic earthquake swarm has been much smaller than the swarms earlier in the month, and is not a cause for great concern. However, the volcano is still in a dangerous state. The continued dome growth means that rockfall activity is likely, and there may be pyroclastic flows into the Tar River Valley. These will generate ashfall downwind of the volcano. The Tar River and Long Ground areas remain especially dangerous and anyone entering these areas is putting themselves at risk of death.

The siren system was tested this afternoon. The sirens will be tested every Wednesday between 3 and 6 p.m. In the event of a change in the alert system, the sirens will be accompanied by messages on Radio Montserrat.

Montserrat Volcano Observatory