Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 6 June
to 4 pm 7 June 1997
The current alert level is ORANGE

The volcano has been quieter today, but another episode of pyroclastic flow activity started in the late afternoon. There have been flows in Tuitt's Ghaut and the Tar River valley, and the cloud lifted for a time so that the dome could be observed.

The pattern of periods of enhanced pyroclastic flow activity continues, with another pulse of activity between 7 pm and 3 am last night. This activity began with a sudden pyroclastic flow in Tuitt's Ghaut, and resulted in a moderate ash cloud which was blown to the west out to sea.

The volcano was quiet for most of the day, and another elevated period began at 4 pm this afternoon. Since then several small pyroclastic flows have occurred, with a large sector of the dome being active from the south-east to the north face above Mosquito Ghaut. The most active area has been the north-east face, with rockfalls and small pyroclastic flows running down the dome towards the Tar River valley.

The volcano has been visible this afternoon, and observers at the airport, Harris and Farrell's have had good views of the dome and the pyroclastic flow activity. There has been some rockfall activity into the top of Mosquito Ghaut, with debris extending about 200 metres from the crater rim. The northern face of the dome is fairly smooth, with no evidence of a channel above the Tuitt's Ghaut. This indicates that only a small amount of material was lost from the dome during Thursday's pyroclastic flows, and any channel that was formed then has been filled in by further rockfall activity.

Seismic activity at the volcano has remained low during the last 24 hours, with an increase in the number of recorded long period earthquakes from 4 yesterday to 9 today. There were also 11 small hybrid earthquakes. The number of rockfall signals was lower, at 64, indicating a general decrease in the intensity of the pyroclastic flow episodes.

Further COSPEC runs were made today between Corkhill and St Patrick's. There is a backlog in the processing of the recent COSPEC measurements, and the recent flux levels will be calculated tonight and reported tomorrow.

The new risk map was published yesterday. Bramble, Bethel, Harris and Paradise have been moved to Zone A. Spanish Point, Farms, Trants, Riley's, Streatham, and Farrell's are now in Zone B, and Zone C includes WH Bramble Airport, Molyneux, Waterworks, and Trant's Yard. Zones A and B are very dangerous and nobody should be in these areas. Pyroclastic flows could easily extend in Tuitt's Ghaut beyond their previous limit at Bramble village. WH Bramble airport remains operational for the time being, although the public are reminded it is open for essential travel purposes only: people not travelling should not visit the airport.

Montserrat Volcano Observatory