Montserrat Volcano Observatory

Weekly Report
Report for the period 5 p.m. 2 April 1999
to 5 p.m. 9 April 1999

Activity at the volcano has been at a slightly higher level this week than over the previous few weeks.

A total of 134 rockfall signals, 2 long period events and 50 volcano-tectonic earthquakes were recorded over the last week. The signals were generally evenly distributed through the week, but there was an increase in rockfall activity on 5 April with a total of 43 events. Since that time, the numbers of earthquakes have been closer to the usual levels over the past few months.

There was a total of 9 ash venting or small explosive events in the last week. The largest event occurred in the evening of 7 April. This event started with a loud rumbling noise and a light coating of sandy ash fell over most of the island. One event on 8 April produced a small pyroclastic flow down the Tar River.

Exceedingly clear views of the volcano were obtained on 6 April. The dome was completely free of cloud, and there was very little steaming from any of the fumarolic areas. No major changes in the morphology of the dome were apparent. Two small ash cones were visible in the bottom of the gully through the dome. These were both in the area above Tar River, and are probably a result of accumulation of ash from the recent spate of ash venting and explosive eruptions.

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