Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 01 April
to 16:00 02 May 1997
The current alert level is AMBER

Activity over the past 24 hours has again been dominated by rockfalls and small pyroclastic flows from the active area in the southern part of the dome. One rockfall was observed from the airport travelling down the southern side of the Tar River Valley. Long-period earthquakes have been the other dominant form of seismic signals recorded by the network. There have also been a slight increase in the number of volcano-tectonic earthquakes recorded today.

The broadband seismic network recorded a total of 91 rockfall signals during the past 24 hours, an increase since yesterday The rockfalls have been occurring on the south-western flank of the dome, shedding material into the upper part of the White River. One rockfall was observed in the Tar River Valley this morning which hugged the southern side of the valley against Perches Mountain. This is the first event of this type to be seen in this area for some time. There were 21 long-period earthquakes, of which 6 triggered rockfalls. The level of long-period seismicity has been above background since the middle of March. Seven (7) small volcano-tectonic earthquake was recorded today. It was not possible to locate any of these events due to their small size. This is the highest daily count of such events since April 5th.

Visibility has been poor for most of the day but some brief views were possible this afternoon. None of the recent rockfalls or pyroclastic flows in the White River have reached very far from the Galway's Wall. A number of small fumeroles were observed low on the north-eastern flank of the dome. No major changes were noted in the dome complex away from the area of active growth above the Galway's Wall.

The data collected from the long GPS occupation of the Hermitage site was processed today. The site continues to move northward at a very slow rate. This movement in no way suggests that a catastrophic failure of this part of English's Crater is likely at the present time.

The volcano remains dangerous, and only essential visits should be made to the evacuated zone. People should wear masks when in the ashy areas. The Tar River and White River valleys are extremely dangerous, and should not be entered under any circumstances.

Montserrat Volcano Observatory