Montserrat Volcano Observatory

Christmas Day - Daily Report
Report for the period 16:00 on 24 December
to 16:00 on 25 December 1995
Merry Christmas!

Four (4) locatable volcano tectonic earthquakes were recorded during this period, with events occurring in the St George's Hill, Centre Hills, Old Road Bay and Long Ground areas at depths of 2 to 4 km. A total of 11 long-period earthquakes were recorded on most of the seismometers. These could not be located, but are probably due to small explosions within the crater area. The general level of seismicity recorded at the Gages seismic station remains low, with the broadband tremor reported yesterday disappearing overnight, although low amplitude, long-period events picked up again after 08:30 this morning, continuing at a rate of about one per minute. A regional earthquake of magnitude 3.7 occurred last night at 18:00, and was located about 100 km from Montserrat.

No EDM lines were measured today. GPS measurements were made at St George's Hill, Reid's Hill and Tar River as usual, although the results will not be processed until the end of the month.

Visual observations were made today from the helicopter and from White's Yard. The large spine reported yesterday collapsed overnight, with only its lower section still intact. Glowing rock avalanches observed in the crater area by Police/Defence force Officers at the airport checkpoint at about 21:19 on 24 December may have coincided with part or all of this collapse. Debris from the spine fell around its base, and material was not carried away from this area. English's crater remains highly active, and recent dome growth was observed in the western crater near the position of the September spine. Vigourous steaming occurred all afternoon, resulting in a large plume of steam which contained small amounts of ash.

Mr. Chandradath Ramsingh of the Seismic Research Unit in Trinidad arrived in Montserrat today 25 December to take part in the monitoring effort. This is Mr. Ramsingh's second tour of duty.

Montserrat Volcano Observatory