Montserrat Volcano Observatory


Daily Report
Report for the period 16:00 on 31 Decemeber 1995
to 16:00 on 1 January 1996


Eighteen (18) volcano-tectonic earthquakes were located during this period at depths in the range 1 to 7 km. Most were clustered just to the north of the active crater area; others were scattered beneath the southern part of Montserrat. Approximately 15 long-period events were recorded on most of the seismometers in the network. Broadband tremor was limited to short periods and was at a very low amplitude on the Gages seismic station. A large regional earthquake was recorded by the local network at 05:38 local time. This event was located about 55 km north of Port of Spain, Trinidad, at a depth of 25 km. The magnitude of this earthquake was 5.0 and it was felt throughout northern Trinidad and as far away as Martinique.

The EDM lines between Castle Peak, Long Ground and White's Yard and between Dagenham, Amersham and Gages Wall were measured today. None of these lines showed any change above the error of the method, continuing the trend of the past 6 weeks or so.

Visual observations were made from the helicopter and from various locations on the ground today in excellent conditions. Dome growth in the eastern sector of the active area has effectively stopped, with very little rock spalling and no measurable growth in height over the past few days. Most of the current activity is centered in the western sector, with a new area of dome growth in a northward direction from the new spine first noted on 26 December. Measurements from Harris' Lookout suggest that there has been no vertical growth of this dome, but it does appear to have grown in volume. Steam production, especially from the northwestern part of the crater, was high all day, and small amounts of ash were noted in the steam plume from time to time.


Montserrat Volcano Observatory