Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 22 November
to 16:00 23 November 1996
The current alert level is AMBER

Rockfall activity at the Soufriere Hills volcano has been at about the same level as yesterday, indicating that dome growth continues. The volcano remains in a dangerous state, and the level of activity could escalate at any time. The number of rockfalls is likely to increase over the next few days to weeks, and there may be pyroclastic flows into the Tar River Valley. The Tar River and Long Ground areas remain especially dangerous and anyone entering these areas is risking death.

The only seismic events recorded by the seismic networks today were 10 rockfall signals. There were no earthquakes. The number of rockfalls was about the same as yesterday, with most of the signals occurring during the night.

The dome has been visible at times today, especially during the early morning. The light and variable wind conditions meant that the steam and gas plume has been rising almost vertically. The top of the October 1 dome is rubbly, and is now clearly visible from the north west of the volcano. Several rockfalls were observed during the day, and there is fresh material in the upper Tar River valley.

The helicopter landed briefly in the Tar River valley this afternoon to collect samples of rock that has fallen from the October 1 dome. This is the first time that the new dome has been sampled, and the rocks will be sent to laboratories in the UK and US for analysis. A sampling expedition was also made to the delta at the foot of the Tar River valley.

The Galways Wall was inspected from the helicopter this afternoon. This is the rock wall above the Galways Soufriere, which forms the southern part of the crater rim. There have been large landslides from this wall during the last two days, and the upper part of the wall is becoming unstable. Further landslides are likely.

EDM measurements were made on the eastern triangle this morning. The lines to Castle Peak have shortened by about 3 cm during the past five days, indicating that the long-term shortening trend continues. A GPS survey today measured a network of four points across Montserrat, and the results are now being processed. No COSPEC measurements were possible because of the wind direction.

Professor Ramsey Saunders and Lloyd Lynch from UWI in Trinidad left Montserrat today after a short visit.

Montserrat Volcano Observatory