Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 9 June
to 4 pm 10 June 1997
The current alert level is ORANGE

The level of pyroclastic flow and rockfall activity was elevated between about 8pm and 1am last night and was followed by a lull in activity until about 8am when a further episode of elevated activity began. This episode is still ongoing and has been characterised by regular rockfalls and several small pyroclastic flows.

Observations of the dome have been hampered by very low cloud today. Nevertheless, between 10.20am and 11.42am four rather slow-moving pyroclastic flows were observed in the Tar River valley. Each of these flows extended beyond the soufriere. Several large rockfalls and a few small pyroclastic flows were also observed in the upper parts of Tuitt's Ghaut today. Rockfall activity continues to occur on the northern, north eastern and eastern slopes of the dome.

Analysis of static photographs taken from Whites Yard on 1 June and 8 June shows that the northern summit of the dome has increased in height during this period by about 25m. The whole northern flank also appears to have advanced northward by about 20m but this is considered to be due to the accumulation of an extensive talus slope.

Seismic activity at the volcano has slightly increased over the last 24 hours with 13 hybrid events, 8 of which triggered rockfalls, and 26 long period events, of which 21 triggered rockfalls. There were a total of 145 rockfall signals recorded, an increase since yesterday.

A COSPEC run was completed today and although the data has not been processed yet, first estimates suggest that the sulphur dioxide flux is about 500-600 tonnes per day. This is similar to the flux of the last few days and indicates that there is still an elevated level of volcanic activity.

A GPS survey was completed today on the northern flanks of the volcano, including Farrell's, to see if there has been any deformation in this area. The results will be processed soon.

Further pyroclastic flows are expected in Tuitt's Ghaut and these could easily extend beyond Bramble village and the junction with Paradise River. The revised zones A and B which include Bramble, Bethel, Harris, Paradise, Spanish Point, Farms, Trants, Riley's, Streatham and Farrell's are extremely dangerous and should not be visited. WH Bramble Airport is operational but the public are reminded that they should only visit the airport if they intend to travel.

Note: the place names used in these reports refer to locations identified on the Tourist Map of Montserrat as a reference, and may not correspond exactly to local variations or popular names.

Montserrat Volcano Observatory