Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 17 July
to 16:00 18 July 1996

The level of volcanic activity at the Soufriere Hills Volcano during this reporting period was similar to that during the previous twenty four hours. Small- to moderate-sized rockfalls from the flanks of the growing lava dome dominated activity.

There were 16 rockfall events detected by the seismic system, compared to 24 yesterday. The largest rockfalls occurred at 22:40 on 17 July and at 05:48, 11:24 and 14:47 on 18 July. The event at 11:24 generated a small ash cloud which could be seen through the cloud drifting over the Upper Gages area. Hybrid and long-period events continue to be recorded at an unchanged level. There were 17 hybrid and 12 long-period events recorded in this reporting period, most of which were small in size. Intermittent, relatively short-duration, low-amplitude broadband tremor was recorded by the Gages seismic station, most probably due to increased steam emissions.

Visibility was good early this morning. No major changes in the dome were visible from the ground, and it was steaming vigorously. Cloud cover made visibility relatively poor for the rest of the day, although some views of the lower flanks of the dome were possible. There were no new deposits on the eastern flanks and no rockfall activity was observed.

EDM measurements were made today on lines in the eastern and northern triangles. The Whites - Castle Peak and Long Ground - Castle Peak lines both show a shortening of 14 or 15 mm over the last two days. This continues the trend seen since early May. The lines in the St George's Hill - Farrell's - Windy Hill triangle continue to show no significant changes.

No COSPEC or GPS measurements were made today. More gravity measurements were taken as part of a survey to make a gravity map of the volcano.

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