Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 20 October
to 16:00 21 October 1996
The current alert level is AMBER

There has been an increase in the level of seismic activity since yesterday. The October 1 dome continues to grow, but no major changes were observed in its shape and size compared to yesterday.

There were thirty-six volcano-tectonic earthquakes recorded during the period. Most of these events occurred in a swarm between 08:33 and 12:30 on 21 October and were located at depths less than 3 km beneath the crater. Four rockfalls and one long-period earthquake was also recorded by the seismic network. The largest rockfall signal occurred at 09:10 today; there no ash clouds associated with this event. Intermittent broadband tremor was recorded on the Gages seismic station from 14:08 on 21 October.

Observation of the volcano from Whites today indicate that there has been no significant visible changes in the appearance of the dome. Very few rockfalls were observed on the eastern face of the new dome.

COSPEC measurements were conducted today along the west coast road from Cork Hill to Gingoes. The results from these measurements are currently being processed.

EDM measurements were carried out on the northern triangle today. The results indicate that line lengths between St George's Hill and Farrells lengthened by 3 mm, while the Windy Hill to Farrells line lengthened by 5 mm. These results continue to indicate that there are no significant changes on this triangle.

The volcano remains in an active and highly dangerous state. Further activity, possibly leading to an explosive event could occur with little warning in the near future. 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.

Mr Rod Stewart of the British Geological Survey arrived on Montserrat yesterday for another tour of duty. Rod would assist with the use of the new Broadband seismic equipment which was recently installed at the MVO.

Montserrat Volcano Observatory