Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 13 October
to 16:00 14 October 1996
The current alert level is AMBER

Activity at the volcano has been at about the same level as yesterday. Seismicity is dominated by the occurrence of small to moderate sized rockfall signals with a few volcano-tectonic events. Growth of the October 1 dome is continuing and some clear views were obtained today.

Five small to moderate sized rockfall signals were recorded by the seismic network during the last 24 hours. Some of these were associated with rockfall activity from several parts of the dome complex. Nine volcano-tectonic events were also recorded; these were all at a depth of less than 4 km beneath the Soufriere Hills volcano. Intermittent low amplitude tremor was recorded on the Gages seismograph station for most of the reporting period.

Visibility was generally poor for most of the day but some brief clear periods allowed good views of the dome. Observations from Whites and by helicopter during the late morning show that there has been notable growth during the past two days with some changes in the shape of the new dome. The eastern edge of the October 1 dome is now a blunt conical peak with slightly more blocky shape than previously noted. Another peak, of similar shape is now also present in the west-south-western side of the dome. Vigorous rockfall activity was noted from several areas on the eastern face. Vigorous steaming was also noted from the southern moat. The height of the October 1 dome was estimated by the helicopter altimeter today to be 2660 ft above sea level.

No EDM measurements were made today. The GPS equipment was used to precisely determine the location of all the new seismic stations.

The COSPEC instrument which was recently returned to the Observatory was used yesterday to conduct measurements of sulphur dioxide emission in the volcanic plume. The results of these measurements are currently being analysed and would be available tomorrow.

The eastern face of the October 1 dome is quite steep, and rockfall activity has increased during the past two days. It is possible that larger rockfalls and possibly pyroclastic flows may occur during the next few days. The volcano remains highly dangerous, and pyroclastic flows could trigger another explosive eruption with very little warning. Everyone who enters the evacuated zone must remain alert and be ready to move at short notice. Individuals who go beyond the Long Ground area into the Tar River valley are risking death. All residents of Montserrat are urged to become familiar with the new alert system and evacuation procedures which was recently published.

Montserrat Volcano Observatory