Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 03 November
to 16:00 04 November 1996
The current alert level is ORANGE.

The level of activity at the volcano has remained high, and there has been another volcano-tectonic earthquake swarm during the last 24 hours. The swarm started last night and is still continuing. Visibility was very poor for most of the day and only limited views of the dome were possible. No major changes were seen.

The volcano tectonic earthquake swarm began at 19:24 last night. So far 139 VT earthquakes have been recorded, along with 2 rockfall signals and three long-period earthquakes. All the VT earthquakes have been at shallow depths beneath the crater. The size of the events has varied, with the largest being about the same size as the maximum recorded during the swarm of 1-2 November. This swarm has not yet reached the intensity of the previous swarm, and earthquakes have been recorded at a maximum of about 10 per hour.

The viewing conditions were poor for most of the day and only brief views were obtained of the crater. The small spine that has been observed over the last few days has changed shape in the last 24 hours. No other changes have been noted.

EDM measurements were completed today on the eastern triangle. The two lines to Castle Peak have shortened by about 17 mm since they were last measured two days ago. This change is consistent with the long-term trend of shortening of 1 cm per day.

A GPS survey was carried out today. Repeat measurements were made of a few lines, to help determine the error in the measurements. The results of yesterday's survey have been processed and no major change in line length were detected.

No COSPEC measurements were made today.

The scientific team at the MVO are very concerned about the high level of seismic activity during the past three 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