Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 27 February
to 6 pm 28 February 1998

Activity over the last twenty four hours has been dominated by two earthquake swarms and a number of large rockfall events. There were also two small pyroclastic flows which were generated on the northern side of the new dome above Galways.

There were 94 hybrid earthquakes, 11 volcano-tectonic earthquake, 1 long period earthquake and 9 rockfall signals recorded between 16:00 yesterday and 16:00 today. A swarm of hybrid and volcano-tectonic earthquakes occurred between 06:33am and 10:17am this morning and consisted of 29 events. A second earthquake swarm occurred between 10:57am and 2:27pm this afternoon and contained 52 events. Rockfalls occurred sporadically throughout the reporting period.

Two small pyroclastic flow signals were recorded, one at 9.14pm last night and one at 1.25pm this afternoon. These flows were generated on the north side of the new dome above Galways. They then travelled down along the western margin of the old October 21st 1997 dome above Farrells and down into the uppermost part of Tuitt's Ghaut. The second of these flows was clearly observed from Garibaldi Hill.

Clear views were obtained of the volcano throughout the day. A dome survey is currently underway and the height of the new dome has been measured at 997m. The summit of the new dome now extends above the dome complex and is very blocky. Ash and steam venting continued throughout the day.

EDM work from Windy Hill has revealed that since 25 January 1998 the northern flanks of the volcano have moved northwards by about 4cm. Much of this movement appeared to occur in the early part of February. There has been little movement over the last few days.

A new dust monitoring site has been established in Old Towne. Dust levels at all monitoring sites including Old Towne were low today.

Residents are reminded to remain alert and listen to ZJB radio.

Montserrat Volcano Observatory