Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 06 October
to 16:00 07 October 1996

Seismic activity at the volcano has continued at a relatively low level during the past 24 hours. Rockfalls are the main seismic signals currently being recorded. The cloud base fluctuated throughout the day and the dome complex was visible from the east; the October 1 dome is still growing at a fast rate.

A total of 23 rockfall events and one hybrid earthquake were recorded by the seismic network. Some of these event were observed by field teams working on the eastern part of the volcano. Most of these events are quite small and only produce very small eruption clouds.

Visibility was quite variable for most of the day, but some views were obtained from the east. The October 1 dome continues to grow and is now estimated to be about 3/4 of the height of Castle Peak dome. The new dome appears to be growing as a single cohesive mass and has not produced any of the spines which were quite common during earlier periods of dome growth. The south-east side of the new dome which faces towards the Tar River Valley is quite steep and may become over-steepened during the next few days. Several photographs were obtained from the Whites EDM site today; these would be compared with photographs taken earlier in the week so as to obtain estimates of dome volume and growth rates.

EDM measurements were conducted today on the eastern triangle to Castle Peak. Low cloud covered prevented measurement along the Long Ground to Castle Peak line. Measurement of the Whites to Castle Peak line indicated no change since this line was last occupied on 03 October. No GPS measurements were made today.

Installation of the new broadband seismic stations continued today and is expected to be completed during the next few days.

The continued rapid growth of the October 1 dome means that rockfalls and possibly pyroclastic flows may occur during the next few days. All indications suggest that these would be mainly confined to the Tar River Valley but may produce ashfalls which would affect areas to the west of the volcano. There is still a lot of ash around, and dust masks should be worn if necessary.

Individuals put themselves in extreme danger if they venture beyond the Long Ground area into the Tar River valley. Further pyroclastic flow activity could start at any time, and could kill anyone in the Tar River valley. Everyone who passes through the checkpoints are reminded that they are entering areas which may become unsafe very quickly, and that they should be on maximum alert at all times while in the danger zone.

Drs Hiroshi Shimizu and Setsuya Nakada of Japan has arrived on Montserrat for a short visit. While on island they would share their experience of the Mount Unzen dome building eruption with scientists at the MVO. Dr William Ambeh also arrived yesterday on a brief stop-over visit to the island. Dr Paul Cole of Luton University also joined the MVO staff during the weekend. Dr Cole would spend about three weeks and will assist with volcanological aspects of the monitoring effort.

Montserrat Volcano Observatory