Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 21 January
to 6 pm 22 January 1998

Seismic activity at the volcano has been at a lower level again today, with a total of 8 hybrid earthquakes, 4 long-period events, 44 rockfall signals and a small volcano-tectonic earthquake. Most of the rockfalls came in a peak of activity late last night and early this morning, although there is some increase in activity at the time of writing. The last few days have seen the return of well-defined peaks in activity, with cycles being about 16 hours at the moment.

Visibility has been very poor for most of today. Small ash clouds have been seen late this afternoon associated with the increase in rockfall activity. Growth appears still to be confined to the southwestern part of the dome and rockfalls are mainly occurring into the upper part of the White River valley. Every indication is that dome growth continues at a high rate, and increases in seismic and other activity can be expected in the days and weeks ahead.

Various field operations were attempted today, although some were curtailed by very poor visibility. GPS lines between Harris Lookout, Roaches Yard and Blake's Estate were occupied but attempts to install new GPS sites in the southern part of the island were thwarted. A successful first occupation of the new Gages Mountain GPS site was made yesterday as a start to establishing a baseline for this site. The survey carried out two days ago between Harris Lookout and Perche's Mountain showed a continuation of the trend of shortening on this line.

Work continues on electronics and telemetry for the broadband seismic network as MVO attempts to bring this important tool back up to full strength with the assistance of technicians from the British Geological Survey in Edinburgh.

Dust levels at the monitoring stations across the island were again low today, thanks to low ash production by the volcano. Slightly raised levels are still being measured at the Catholic Primary School, and an additional type of sampling is under way to establish the source of this dust.

People should remain alert and listen to Radio Montserrat for further information.

Montserrat Volcano Observatory