The level of activity at the volcano has remained at about the same level during the past 24 hours, with very few earthquakes and continued growth of the 1 October dome.
The seismic activity has been at a low level, with only one VT earthquake recorded. There have been 16 rockfall signals. The largest of these, at 02:24 and 02:49 this morning, were among the largest rockfalls recorded recently. There were also three episodes of broadband tremor recorded at the Gages seismic station.
Visibility was very good yesterday afternoon and for most of the day today, which has allowed further dome surveys to be undertaken. Photographs were taken from fixed points around the volcano, which will allow accurate determination of the volume of the dome complex. The October 1 dome has grown substantially during the last 24 hours, and has steep sides and a flat top. It has increased in height and spread further to the south. Measurements made last night from the helicopter suggested that the dome was about 200 ft high, but these results still need to be checked. Rockfalls were observed today from the October 1 dome and the scar caused by the 17/18 September explosive eruption.
Two more sites of the new seismic network were prepared at Windy Hill and Garibaldi Hill. New stations were installed at the Galloways and St Georges Hill stations, and the radio equipment to relay the seismic signals to the Observatory should be completely installed tomorrow.
The continued rapid growth of the October 1 dome means that rockfalls and possibly pyroclastic flows will occur during the next few days. These will result in ash clouds. There is still a lot of ash around, and dust masks should be worn if necessary. Individuals put themselves in extreme danger if they venture beyond the Long Ground area into the Tar River valley. Everyone who passes through the checkpoints are reminded that they are entering areas which may become unsafe very quickly, and that they should be on maximum alert at all times while in the danger zone.
Drs Simon Young and Bill McGuire left Montserrat today to return to the U.K. Dr Young will return in three weeks. Drs Willy Aspinall and Ricky Herd arrived at MVO on Tuesday. Dr Aspinall will be working with seismic data from the new seismic network, and Dr Herd will help with GPS surveys.