Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 16 June
to 4 pm 17 June 1997
The current alert level is ORANGE

Following the pyroclastic flow activity yesterday in Gage's valley and Mosquito Ghaut, which extended into the present reporting period, activity on the dome has been at a much reduced level today.

The level of pyroclastic flow and rockfall activity declined steadily through the evening hours, but then picked up slightly between 4am and 9am this morning. This activity comprised rockfalls and small pyroclastic flows in Mosquito Ghaut and into the Tar River valley. Since then there has been a steady decline to a much lower level.

The Gages wall and Mosquito Ghaut were inspected this morning from the helicopter. There was little evidence of change to the Gage's wall part of the crater as a result of yesterday's activity: the material feeding the pyroclastic flow appeared to have come down from high on the dome, and skipped over the wall into the valley. The main area of activity above Mosquito Ghaut has cut a narrow chute into the dome.

The seismic activity today has been similar to that of yesterday, with rockfall signals dominating: there were 187 of these in the last 24 hours. The level of earthquakes remained low, with no volcano-tectonic earthquakes, 5 hybrid events and 4 long-period earthquakes recorded.

COSPEC runs were made along the road to the south this afternoon. The most recent measurements, made on 16 June, gave an average of 409 tonnes/day from three runs.

GPS measurements indicate that the rate of movement of Chance's Peak to the west-south-west has slowed. Measurements from other lines are currently being processed.

There has been cloud over the volcano for most of the day, although the recent haze has dispersed. Only the lower talus slopes of the dome and the ghauts below the crater rim have been visible to observers today.

Further pyroclastic flows could occur in any direction, especially in Mosquito Ghaut, Tar River valley or Gages Valley. Access to Plymouth remains restricted pending a review of the situation by the authorities. Corkhill remains safe at this time. WH Bramble Airport reopened this morning after the precautionary closure yesterday afternoon, and flights have been operating normally.

Montserrat Volcano Observatory