Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 23 June
to 16:00 24 June 1996

Activity at the Soufriere Hills Volcano has been at a low to moderate level, slightly higher than over the last four days. The activity was dominated by small rockfalls from the growing lava dome.

A total of 62 rockfall events were recorded during this period, almost identical to the count yesterday. Most of these signals were very low in amplitude and short in duration, although a series of signals occurred between 20:56 and 21:18 on 23 June which may have been the result of small pyroclastic flows. There were 3 hybrid events and twenty small long period earthquakes. Tremor was at a very low level during this period.

Visibility was slightly better today than over the previous few days, and a helicopter flight enabled good views of the lower flanks of the dome. As expected, there were no major new deposits on the lower flanks, although new material was noted to the south of Castle Peak in the upper reaches of the South Fork of the Tar River. Little new material has fallen into the upper part of Fort Ghaut as yet, although the full width of the Gages Wall is now filled with debris from the dome. It is still not clear which areas on the upper flanks of the dome are most active, although growth is clearly still continuing.

COSPEC measurements were carried out today; a sulphur dioxide flux of about 76 tonnes per day was measured, somewhat lower than the past few measurements.

EDM measurements were not made today due to the poor viewing conditions on the west of the volcano and the inability to get reflections from the Castle Peak reflector due to ash; it is hoped that this ash can be cleaned off soon. GPS surveys were done on the western network today and also preparations were begun for installation of two permanent GPS receivers on the western and eastern flanks of the volcano to measure the long term changes in the shape of the volcano.

Despite the continued relatively low level of activity, the volcano remains highly dangerous to people and property on both it's eastern and upper western flanks. People who make visits to the evacuated zones expose themselves to various levels of risk, depending on the area entered. Such visits 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 high risk zones. All access roads to these areas remain 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