Montserrat Volcano Observatory

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

The relatively low level of activity observed at the Soufriere Hills volcano during the past several days continued during the period of this report. Again, small- to moderate-sized rockfalls from the flanks of the growing lava dome dominate the seismic records.

Twenty one (21) rockfall, 4 long-period and 4 hybrid events were detected. The largest rockfalls occurred at 02:19 and 08:16 on 20 July. A rockfall at 16:04 today resulted in a moderately thickish ash cloud which could be seen drifting in a westerly direction over the Upper Gages, Amersham and Plymouth areas. Episodes of low- to moderate-amplitude broadband tremor, with durations ranging from a few minutes to several hours, were fairly common on records of the seismic stations closest to the volcano. The increased tremor is interpreted as being due to increased steam emission from the crater.

Visibility was very poor throughout the whole observation period.

Gravity and GPS measurements were carried out on the northern flank of the volcano but the results are still awaited. An attempt to perform COSPEC measurements was made but had to be aborted because of instrumental problems. EDM measurements were not made because of the low cloud cover.

The Soufriere Hills Volcano is still considered to be highly dangerous to people and property on it's eastern and upper western flanks. Visits to the evacuated zone must be kept to a minimum. The Tar River and Long Ground areas to the east and upper Fort Ghaut, Gages Village and Upper Amersham areas to the west are all extremely dangerous. All access roads to these areas remain closed and 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