Montserrat Volcano Observatory


Morning Report
Report for the period 16:00 23 December
to 07:00 24 December 1996
The current alert level is ORANGE


The crater area of the dome is relatively clear this morning and a viewing flight is under way.

The hybrid seismic activity which started yesterday continued overnight and is now showing a clear 'banded' nature similar to that seen in late July of this year. Every 7 to 8 hours or so, a peak in seismic energy is occurring which is related to the amount of hybrid and rockfall activity. At the peak of each cycle, the hybrid earthquakes merge into seismic tremor. Each peak is at a higher level than the last so that this particular style of activity is still building up.

The re-appearance of 'banded' seismicity is probably related to rapid dome growth and presents the strong possibility of further dome collapses and pyroclastic flow generation. Pyroclastic flows should be confined to the Tar River valley, although a northward shift in the focus of dome growth has meant a greater possibility of rockfalls from the northern and northwestern flanks of the dome. The Galway's Wall remains unstable, although the pressure on it appears to have eased and any major collapse should be preceded by some further build-up in rock avalanche activity from the wall.


Montserrat Volcano Observatory