Montserrat Volcano Observatory


Daily Report
Report for the period 16:00 on 26 December
to 16:00 on 27 December 1995


Three (3) volcano-tectonic earthquakes were located during this period. Two occurred beneath the Soufriere Hills volcano and the third was in the Long Ground area, all at depths of 0-5 km. Twelve (12) long-period events were recorded by most of the seismometers in the network. Small, repetitive long- period events are still being recorded at the Gages seismic station; these continue at very low rates and amplitudes. One of the larger long period events of the day was associated with a small explosion and rock fall from the active dome area which was witnessed by scientists.

EDM lines were measured today to Castle Peak, Chances Peak and Gages Wall; these data are still being processed. EDM data collected yesterday were processed overnight. None of the lines showed any change. GPS measurements were made today at St George's Hill and Tar River. At 17:00 on 26 December, the receiver previously placed at Chance's Peak was removed; it was reinstalled at Reid's Hill today. The GPS data will not be processed until the end of the month.

Visual observations were made today from the helicopter and from White's Yard. From the measurements at White's, the spines have remained at the same height, but the upper surface of the dome has risen by approximately 5m (15ft) in 24 hours. The top of the dome is now clearly visible from Windy Hill round to Long Ground. Numerous rock falls were observed, some of which generated small ash-rich plumes. One of the larger rock falls was witnessed during a helicopter flight this afternoon. A new spine, first observed yesterday afternoon, has grown significantly in the last 24 hours. The crater continues to steam vigorously from numerous small vents.


Montserrat Volcano Observatory