Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 04 November
to 16:00 05 November 1996
The current alert level is ORANGE.

The level of activity at the volcano has remained high, with the continuation of the volcano-tectonic earthquake swarm during the last 24 hours. Visibility has been good this afternoon. No major changes in the crater area were seen, although a new spine has appeared.

The volcano tectonic earthquake swarm which began in the evening of 3 November has continued, with a total of 175 VTs recorded during the period. There have been up to 11 earthquakes per hour, and the rate has decreased steadily during today, although the earthquakes were still continuing at 16:00. The maximum size of the earthquakes has been as large as during the 1-2 November swarm. All the earthquakes were at shallow depths beneath the crater. Four small rockfalls and one long-period earthquake have also been recorded.

The viewing conditions were poor this morning, but cleared up this afternoon, allowing observations to be made from the helicopter. There is an active area on the top of the October 1 dome, which has a blocky appearance and is surrounded by ashy deposits. There is at least one new spine in the southwest of the dome, and the spine that has been observed during the last few days is now slightly bigger and shaped like a pyramid. The eastern face of the dome is still inactive, as has been observed on previous days, although one small rockfall was seen from it. The October 1 dome was steaming vigorously, particularly from the western side.

EDM measurements were completed today on the northern and eastern triangles. Preliminary processing of the results shows that the long-term trends for these triangles are continuing. No GPS measurements have been undertaken.

Four runs with the COSPEC instrument were made to measure the amount of sulphur dioxide coming from the volcano. Preliminary analysis of the measurements suggests that the amount of gas is slightly lower than during previous days.

The scientific team at the MVO remain highly concerned about the high level of seismic activity during the past few days. However, the scientists cannot be sure that the earthquake swarms will lead to a potentially dangerous volcanic explosion in the near future. We advise that the alert level remains at Orange and that it may be a few days before the alert level can move down again. We stress that the volcano is still in a very dangerous state and that all residents should follow the recommendations laid out in the alert procedures, and listen to Radio Montserrat.

Montserrat Volcano Observatory