Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 19 June
to 16:00 20 June 1996

Activity at the Soufriere Hills Volcano has remained at a relatively low level today. It was dominated by generally small rockfalls and intermittent low amplitude broadband tremor.

A total of 63 rockfall events were recorded during this period, somewhat fewer than yesterday. The largest rockfalls occurred at 13:29 and 13:54 on 20 June. No ash clouds were visible from these events, due probably to the low cloud. There was 1 large long-period event and 7 hybrid events. Intermittent low- to moderate-amplitude broadband tremor was recorded throughout the reporting period on the stations closest to the volcano; this was strongest in the early morning of 20 June.

Viewing conditions have again been poor. No sightings of the dome were possible today. A measurement to the top of the dome late yesterday showed that the top of a spine-like feature in the summit area was at a height of 3092 ft above sea level.

EDM measurements were not made today due to the weather. Yesterdays results showed shortening of 2.5 cm over a five day period on the lines from White's and Long Ground to the Castle Peak reflector. This continues the as yet poorly constrained trend of the past 3 weeks or so, with movements averaging 3 to 5 mm per day. This enhanced rate of shortening coincides with an increase in volume of dome rock piling against the west side of Castle Peak. The Farrell's reflector showed no movement within the error of the technique.

COSPEC measurements of the SO2 flux in the plume were again made today - results are still being processed although initial indications suggest a lower flux than yesterday. A well-defined plume was present yesterday, giving a total SO2 flux of about 170 tonnes per day, slightly higher than for the previous few days.

Lutchman Pollard of the SRU returned to Trinidad today after a 4-week tour of duty.

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 it's eastern and upper western flanks. 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 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