Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 14 June
to 16:00 15 June 1996

Activity at the Soufriere Hills Volcano was higher during this reporting period with notable ash emissions late in the afternoon of June 14. These occurred during a sustained period of heavy rainfall, which is believed to have had significant influence on their generation. There was ashfall to the northwest of the volcano, in the St George's Hill, Cork Hill and Old Towne areas.

A total of 198 rockfall events were recorded during the reporting period, a significant increase from the 34 recorded yesterday. Rockfall activity had started to increase from 14:00 on 14 June. The largest rockfalls were recorded at 16:25 and 17:12 on 14 June. The seismic signals from these events were similar to those seen from small pyroclastic flows in the past. Small repetitive hybrid events appeared at a rate of about one every five minutes before the rockfall activity started. These hybrid events increased in number overnight to about one per minute. They also doubled in amplitude. They have decreased in number and size and are now one every 4 minutes or so.

Viewing conditions were very poor today due to cloud cover. In the early afternoon, a small pyroclastic flow was seen occurring in the south fork of the Tar RIver to the south of Castle Peak. During helicopter inspection at 14:00, this flow, or perhaps a previous one, was seen to have travelled perhaps 1000 ft from the dome. There was clear evidence of two small pyroclastic flows which had entered the Upper Tar River Valley. One of these had come from the eastern flank of the dome and the other from the northeastern flank. Both had travelled onto the broad block and ash fan and must have occurred after the rainfall of yesterday evening as they were deposited on top of wet older deposits. It was not possible to see into the Upper Fort Ghaut area but it is suspected that some material fell down into this area producing some of the ash which fell last night. Semi-continuous ash production was noted between about 18:00 and 19:00 on 14 June at a time of high rockfall activity and also heavy rain.

EDM measurements were made today on lines in the western triangle. The changes in line length to the Chances Peak steps reflector were consistent with past results, with movements of less than 1 mm per day recorded.

COSPEC measurements were made today between Cork Hill and Kinsale beneath the gas and ash plume from the volcano. No results are yet available for the 4 runs made.

GPS measurements were made today on the western and northern flanks of the volcano. The results have not yet been processed. Results from surveys of yesterday suggest no movement above the error of the method for the eastern network.

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. Those who must visit the evacuated areas are also reminded to stay away from the ghauts. The recent rainfalls will mobilise loose ash and soil to produce mudflows. 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