Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 10 June
to 4 pm 11 June 1997
The current alert level is ORANGE

Volcanic activity continues, with small pyroclastic flows in Tuitt's Ghaut and Tar River valley. The activity is still periodic, and repeats every 16 hours or so. During the last three days the intensity of each pulse has increased gradually, and the length of each episode has become slightly longer.

The latest pulse of activity was between 3 am and 11 am this morning. The observer at the airport reported that only a few small pyroclastic flows were visible during this period, with the activity divided between Tar River and Tuitt's Ghaut.

Seismic activity at the volcano has remained at about the same level, with 20 hybrid and 15 long-period earthquakes. About half of these earthquakes triggered rockfalls, and there were a total of 135 rockfall signals. There was one volcano-tectonic earthquake which was located at 2 km beneath the Gages area. A regional earthquake close to Guadeloupe was also recorded.

A helicopter trip was made to the delta at the base of the Tar River valley to sample the contentious, high velocity pyroclastic flow of 27 May which reached the delta.

Further COSPEC measurements were made today, but the results have not been processed. They will be reported soon.

An EDM survey of the western triangle was attempted this morning, but had to be aborted because of light ash fall.

Further rockfalls and pyroclastic flows are expected, and could easily extend down Tuitt's Ghaut beyond Bramble village. Zones A and B on the risk map should not be visited. 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