Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 30 April
to 16:00 01 May 1997
The current alert level is AMBER

The volcano has been relatively quiet during the last 24 hours, with rockfalls and small pyroclastic flows dominating activity. Long-period earthquakes continue to be recorded at above background levels. Low cloud has restricted views of the top of the dome.

The broadband seismic network recorded a total of 67 rockfall signals during the past 24 hours, a slight 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. There were 21 long-period earthquakes, of which 9 triggered rockfalls. The level of long-period seismicity has been above background since the middle of March. One volcano-tectonic earthquake was recorded today, but no hybrid events.

Visibility was poor today, and no views of the dome were possible. Small ash clouds have been generated from the rockfalls, but ash fall has been very light.

The GPS equipment was retrieved from the Hermitage site this afternoon. These data are currently being processed and the result will be available tomorrow. The GPS data collected over the past couple of days has been processed today. The site on Chance's Peak has moved 73 millimetres toward the west-south-west since it was last measured on January 18th, 1997. The site above Farrell's on the crater rim has continued to move toward the north-east but at a much slower rate than previously.

EDM measurements have been made on the lines between Lower Amersham to Upper Amersham and Lower Amersham to Chance's Steps. The Amersham - Chance's Steps line has extended by 14 millimetres since it was last measured on March 27th, 1997. The Lower Amersham - Upper Amersham line has shortened by 30 millimetres since the last measurement on April 8th, 1997. These lines have shown erratic jumps in the past but are generally showing very slow shortening trends.

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