Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 29 November
to 16:00 30 November 1996
The current alert level is ORANGE

Activity at the volcano has increased today with the onset of another swarm of volcano-tectonic earthquakes. The level of surface activity was low, with only a few rockfalls from the October 1 dome. Further inspections of the Galway's Wall showed that little further disintegration has occurred in the past 24 hours, but the wall remains very unstable. Further avalanches from the Galways Wall could happen at any time. A major collapse of the wall could expose hot, gas-rich magma from the lower sections of the dome, and trigger a lateral blast. This has the potential to cause major damage to St Patrick's and the surrounding areas, and the death of any one in the area. The October 1 dome is still growing, and further rockfalls and pyroclastic flows are likely down its southeastern and northeastern flanks. This means that the Tar River and Long Ground areas are especially dangerous and anyone entering in these areas is risking death.

Inspections were made of the Galway's Wall during the day, both from the helicopter and from the new observation point, which was completed today. No new landslides were noted and no further visible opening of cracks was noted. However, the wall remains very unstable and further minor or major collapses could occur at any time.

Seismic activity has been at a higher level today than over the past few days, with the onset of a new swarm of volcano-tectonic earthquakes. A total of 20 VTs have been recorded since 06:45 this morning, all located at depths of less than 2 km beneath the crater. In addition to the VTs, 4 rockfall signals and one long-period earthquake triggered the seismic network.

Some visual observations of the dome were possible from the helicopter and from Whites again today. Rockfalls continue from the northeastern and southeastern flanks of the dome, which is still growing at a moderate rate. Steaming continues from a number of places on the dome, most notably in the southern area close to Castle Peak.

EDM measurements were made on the eastern triangle today. There was some slight shortening of the lines to Castle Peak.

Much work has been undertaken today by MVO scientists, in conjunction with colleagues around the world, to better quantify the dangers of collapse of the Galway's Wall. This work continues and will be enhanced with the arrival of Dr Barry Voight from the USA on Monday. Further details will be given of this work when complete.

Montserrat Volcano Observatory