Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 15 June
to 16:00 16 June 1996

Activity at the Soufriere Hills Volcano has remained at a moderately high level. There were a number of small pyroclastic flows on the eastern side of the volcano. These generated ashfall in Plymouth and surrounding areas.

A total of 149 rockfall events were recorded during this period, compared to 198 yesterday. The largest rockfalls were at about 17:00 on 15 June and between 09:48 and 10:05 on 16 June when rockfall signals were almost continuous. The small repetitive hybrid events seen during the last few days continued to occur at a declining rate and with slightly increased amplitude during the reporting period. In the afternoon of 16 June, they were occurring at a rate of only two or three per hour. There were 21 well-recorded hybrid events and 15 long-period earthquakes during the reporting period. There was some low-amplitude broadband tremor between 17:05 and 18:00 on 15 June and from 01:10 to 02:15 on 16 June.

Viewing conditions were very poor and it was not possible to see the dome at all. A series of small pyroclastic flows were seen from Bramble Airport, starting at 09:52 on 16 June. These travelled down the valley on the southern side of Castle Peak. The first travelled about 2,500 ft from the dome, and set fire to a few trees. This was larger than any previous flows in this area. The second flow, at 09:57, did not travel as far as the first. There then followed a series of smaller flows. The larger flows generated a moderately thick ash cloud which drifted westwards on the wind and there was ashfall in Plymouth and the surrounding areas. From a helicopter inspection, it was clear that these flows were not as hot as previous ones since many trees were covered in ash, but not burnt. The inspection also showed that there had, at some time, been a small pyroclastic flow from the northeastern part of the dome, which travelled about 1,000 ft from the dome. There were further small pyroclastic flows seen in area south of Castle Peak at 10:21, 11:40 and 13:07. No views of the upper Fort Ghaut area were possible so that the amount of new material in that area remains unknown.

No EDM measurements were made today. GPS measurements were made, but the data has not yet been processed.

No COSPEC measurements were made today. The results from yesterday show an average SO2 flux of 135 tonnes per day, consistent with recent low results.

Scientists at the Montserrat Volcano Observatory remain highly concerned about the current state of the volcano and the dangers to people and property on both the eastern and upper western flanks of the volcano. Visits to the evacuated zone should be kept to an absolute minimum. The Tar River, Long Ground and Whites areas to the east and upper Fort Ghaut, Gages Village and Upper Amersham areas to the west are all now extremely dangerous. The road between Lee's Estate and Ryners Village remains closed. People should not enter these areas under any circumstances. If they do, they put themselves and others at direct risk of serious injury or death.

Montserrat Volcano Observatory