Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 14 January
to 16:00 15 January 1997
The current alert level is ORANGE

During the past 24 hours there was a reduced level of activity at the volcano. Rockfall and pyroclastic flow activity from the dome continued but at a lower level than the last few days. Seismic activity was also at a low level with a marked reduction in the number of earthquakes that were recorded. Poor visibility inhibited visual inspection of the Galway's Wall which showed evidence of becoming more active yesterday. The entire south-eastern part of the dome however remains in an unstable state, and further pyroclastic flows are likely in the next few days. A major collapse of the dome is possible, and could result in another violent explosion, similar to that of September 1996. However, it is expected that there would be several hours of a high level of pyroclastic flow activity before any explosion. Zone E, which includes Cork Hill and the airport, remains safe.

A total of 39 rockfall signals and 7 volcano-tectonic earthquakes have been recorded in the last 24 hours. Five (5) hybrid and 4 long period events were also recorded. The low level of seismic activity does not signal a reduction in the overall level of hazard. Vigorous steam venting occurred from the north-eastern sector of the dome for most of the reporting period. During the most intense periods, 12:10 am to 2:20 am and 9:40 to 11:20 am, moderate level seismic tremor was observed.

Small pyroclastic flows were seen coming from the south-eastern section of the dome. Most, if not all of the flows travelled only to the break in the slope at the base of the dome.

No COSPEC nor gravity surveys were carried out today. The gravity and dome volume field teams opted process data today. A field crew visited the Tar River valley and the delta to study the recent pyroclastic deposits. The surge deposits in the valley near the entry point measured in excess of 200 degrees centigrade. The temperature of the flow deposits on the delta, 2 to 3 meters from the sea was about 320 degrees centigrade. This was measured 25 centimetres into the flow.

Montserrat Volcano Observatory