Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 22 April
to 16:00 23 April 1997
The alert level was reduced to AMBER this morning.

The level of rockfall activity has been high during the last 24 hours, with almost continuous rockfalls from the south of the dome. This has resulted in almost continuous ash production, with light ash fall in Corkhill. Salem and Old Towne.

The broadband seismic network recorded 136 rockfall signals. This is an increase since yesterday, and one of the highest number of rockfalls recorded this year. Most of these rockfall signals have been small. There were also 24 long-period earthquakes, and no hybrid or VT earthquakes.

Visibility has been fairly good, and observations were made from the summit of South Soufriere Hills this morning. Near-continuous rockfalls and pyroclastic flows were seen and heard coming from the dome above Galway's Wall. The pyroclastic flows were small, and none reached beyond the soufriere area. The dome could not be seen clearly because of the continuous ash production, but new growth was noted at the top of the dome.

The long GPS survey which started yesterday was completed this morning, and the results are now being processed. Yesterday's EDM results showed a small increase in length of the lines to Farrells. The measurements of this line in the last few weeks have been erratic, probably because of poor atmospheric conditions. The lines show a very slow trend, with the distances from Farrells to Windy Hill and St George's Hill gradually shortening.

The alert level is now Amber. However, the events of the last 24 hours show that the level of volcanic activity is changeable, and it may be necessary to increase the alert level again. Further ash fall in the safe zone is expected, and so residents should always walk with an ash mask. The Tar River and White River valleys are extremely dangerous.

Late note: Further pyroclastic flow activity occurred at 5 pm tonight, resulting in an ash cloud which rose to about 7,000 ft and was blown to the north-west. Further updates on the situation will be broadcast on Radio Montserrat as required.

Montserrat Volcano Observatory