Montserrat Volcano Observatory

Weekly Report
Report for the period 5 p.m. 23 April 1999
to 5 p.m. 30 April 1999

Activity at the volcano has been generally about the same level as last week.

A total of 89 rockfall signals, 3 long period earthquakes and 71 volcano-tectonic earthquakes were recorded over the last week. The signals were evenly distributed through the week.

There were only 2 ash venting or small explosive events in the last week. The first occurred early on the morning of 25 April; light ash fall was experienced in parts of the northern zone, and fresh new blocky deposits could be seen on the upper part of Farrell's Plain. Strong fumarolic activity was also observed in the northern lobe of the dome, and observation flights later in the week showed that a gully in this northern lobe was developing. The second event occurred at lunchtime on 30 April and produced an ash cloud that drifted to the north-west.

Occasional observations during the week showed that fumarolic activity was still vigorous in the area at the top of the Tar River valley.

GPS occupations of Long Ground and Windy Hill in conjunction with the permanent stations at Hermitage, Harris, Mongo Hill and South Soufriere were completed this week, and results will be reported later.

Measurements on the EDM network in Long Ground were also completed this week. There are no consistent movements of the sites at the moment.

Residents of Montserrat are advised to keep listening to ZJB Radio Montserrat for information in case of any changes in the state of the volcano.

Montserrat Volcano Observatory