Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 17 December
to 6 pm 18 December 1997

The volcanic activity has been at a slightly higher level, with more rockfall signals being recorded today than over the last few days.

Unfortunately the broadband seismic system is still out of action today. The short period system is also experiencing a back log of events for characterisation due to a high level of noise a few days ago. Hence there are no earthquake counts for today. However, the number of triggers on the short period system today has been slightly higher than over the last week, and the overall amplitude of the seismic energy has been larger. From the drum records the number of hybrid events and rockfall signals has also been greater than recently.

Observations today showed that most of the rockfall activity was concentrated over the Galways area, but there were also several rockfalls to the east down the southern part of the Tar River valley.

A GPS survey of the eastern network including Harris Lookout, Windy Hill, Hermitage, Long Ground and Lees Yard was completed today, and the data are currently being processed.

Air quality in the north of the island is good, but south of Lawyers Mountain the levels of dust were slightly raised.

Although activity is still subdued and mainly focused in the southern central part of the volcano, the area of growth on the dome can change very quickly. Growth activity appears now to be backing up behind the major build-up of material in Galways, and a renewal of rockfalls or pyroclastic flows down Gages or Tar River would not be a surprise in the near future.

Today, Professor Steve Sparks of Bristol University joined the staff of MVO once again as Chief Scientist, and Mr Graham Ryan of Lancaster University left Montserrat at the end of his tour of duty.

Montserrat Volcano Observatory