Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 on 08 December to
16:00 on 09 December 1995

Twenty one (21) earthquakes were located during the period. Most of these occurred beneath the Soufriere Hills volcano at depths of 0 to 3 km (0 to 2 miles) although one was located about 7 miles offshore from Roache's Yard at a depth of 8 km (5 miles). The level of seismicity has continued to decrease, with only short periods of low amplitude tremor being recorded only at the Gages seismic station. Several large long-period events occurred overnight, and the small, frequent long-period events recorded over the last few days have almost stopped completely this afternoon. The level of seismicity is now at a lower level than at any time since 26 November. A mudflow signal was recorded at Gages at 04:34 this morning following a period of heavy rain. The signal lasted for about 20 minutes.

The EDM field team has been operating throughout the day. The lines at Tar River were measured this morning, and showed no change. Low cloud levels on the volcano have prevented measurement of any of the other lines. Two new sites were established to measure the position of the new Gages Wall reflector. GPS measurements were again made overnight at stations at Harris' Lookout, Radio Antilles Aerial and St. George's Hill. The results from these measurements as well as the new line at Roche's Yard have not yet been processed due to a technical problem which is expected to be overcome tomorrow.

Visual observations of the crater area were not made today due to low cloud cover. Two small ash explosions occurred at 14:19 and 15:20, with very light ashfall reported by scientists in the Amersham area. A brief sighting of the dome from the Tar River area suggested that the rate of growth of the dome has slowed since yesterday.

Installation of a new 3-component seismometer station was completed late yesterday on South Soufriere Hill. Minor adjustments to the station were made today and the data are now being recorded at the observatory. This station will enable scientists to more accurately locate earthquakes occurring beneath the Soufriere Hills volcano.

Montserrat Volcano Observatory