Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 22 January
to 16:00 23 January 1997
The current alert level is ORANGE

The volcano has remained in a quiet state, with the seismic activity dominated by two volcano-tectonic earthquake swarms. There has been poor visibility all day, and no views of the crater area have been possible.

A total of 71 volcano-tectonic earthquakes were recorded, in two swarms between 5:50 pm and 9:15 pm last night and 5:40 am and 07:25 am this morning. The first swarm was the largest, with 48 earthquakes. Eight hybrid and six long-period earthquakes were also recorded. The long-period earthquakes occurred after the end of the earthquake swarms. There were 31 rockfall signals.

Two flash floods in Fort Ghaut were recorded by the Gages seismic station, at 8:15 am and 10:50 am. The floods caused more material to be deposited in the lower reaches of the Ghaut in Plymouth.

MVO fieldwork today has been hampered by low cloud and rain. Observers at Whites this morning were not able to see the top of the dome, and thus it is not possible to say if the rapid dome growth has continued since yesterday.

The COSPEC measurement made on 21 January has been calculated, and gave a result of 1260 tonnes per day. This is a high value, and is similar to other values in the past weeks that have been made following collapses of the dome.

All the signs are that the current phase of activity has continued, with dome growth in the south-eastern sector of the dome. Further pyroclastic flows are likely in the next few days. Although the dome is likely to collapse in small chunks, producing small to large pyroclastic flows, a major collapse can not be ruled out. Should this occur, another explosion similar to that of September 1996 could result. It is however expected that there would be several hours of high level pyroclastic flow activity before any explosion. Zone E, which includes Cork Hill and the airport, remains safe.

Montserrat Volcano Observatory