Montserrat Volcano Observatory


Morning Report
Report for the period 16:00 30 December
to 07:00 31 December 1996
The current alert level is ORANGE


Seismic activity has remained at a relatively high level, with continuation of the bands of tremor and hybrid events which re-appeared yesterday. The bands are currently about 5 hours apart, with the largest one of this set (in terms of seismic energy) being at about 7 pm yesterday evening. The two since that time have been slightly smaller and all are smaller than the similar bands seen a week ago. In addition to the tremor and hybrid events, rockfall signals continue to be recorded - almost all are thought to be coming from the active area on top of the October 1 dome.

Visual observations of the glowing dome were possible last night; rockfall activity appeared to be semi-continuous and at a similar level to that seen over the past few days. Of particular note was the large amount of material falling down the outside of the pre-September dome on its northern flank. This material is coming to rest against the Farrell's Wall, which may soon be overtopped if activity continues at the current rate.

The most immediate dangers from the volcano remain in the Tar River valley and surrounding areas, where pyroclastic flows are likely to be generated at any time. Overtopping of the Farrell's Wall would rapidly endanger the area to the north of the crater, including the central corridor route. Rapid dome growth has in the past led to large dome collapses, generation of pyroclastic flows and ash clouds and on one occasion to an explosive event. None of the above phenomena can be ruled out for the current phase of activity over the next few days to weeks, especially if the rate of dome growth continues to be very high.


Montserrat Volcano Observatory