Montserrat Volcano Observatory

Morning Report
Report for the period 16:00 10 December
to 07:00 11 December 1996
The current alert level is ORANGE

The level of seismic activity has remained high during this period, with the latest swarm of volcano-tectonic earthquakes continuing. The rate of occurrence of earthquakes is somewhat lower than that during much of the previous swarm, but the magnitude of the largest events remains at around 3 on the Richter Scale. A total of 71 earthquakes were recorded overnight. The Galway's Wall continues to collapse, with 7 landslides recorded by the seismic network during the period since 4 pm yesterday.

Further measurements of the cracks on Chance's Peak were made late yesterday afternoon - the cracks continue to show movement of the southern part of Chance's Peak. EDM measurements to Castle Peak showed movements of just under 1 cm per day shortening, confirming the recent increase in the rate of deformation of the eastern flank of the old dome.

The situation at the volcano continues to be extremely serious, and the scientists fear that we may be moving towards an explosive eruption. If the Galway's Wall or the dome collapse, there is a serious risk of lateral blasts that could cause pyroclastic flows and surges in any direction around the volcano. Such an event could occur at any time with no warning. The revised risk map is still in operation, and zone A/B is extremely dangerous. We urge that nobody should be in this area today.

Dr Barry Voight left Montserrat this morning after a 10 day visit. The MVO will remain in close contact with Dr Voight and would like to thank him for his highly valued input to the monitoring efforts.

Montserrat Volcano Observatory