Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 25 May
to 16:00 26 May 1996

Volcanic activity at the Soufriere Hills volcano during this period has been at about the same level as that which obtained yesterday. Seismicity continues to be dominated by small- to moderate-sized rockfall signals. Although none of the rockfalls were particularly large, most generated small ash plumes. Due to very still environmental conditions most ash plumes were near vertical and some attained heights of up to 6000 ft above sea level.

There were 14 long period events and three hybrid earthquakes recorded today. The level of low-amplitude broadband tremor decreased during the period and has been intermittent since about 02:30 on 26 May.

Excellent viewing conditions throughout the day allowed very good views to be obtained of English's Crater from the helicopter, Brambles Airport and from several other areas around the volcano. The active areas of dome growth are now the eastern, northeastern, western and southern parts of the dome. The top of the dome consist of several small spines with morphology quite similar to the old Castle Peak; none are higher than 20 m above the main part of the dome. Vigorous steaming was seen from several areas of the moat, with the southern, northeastern and western parts being most energetic. Rockfalls on the eastern flank of the dome continue to occur from a large scar which is located in the vicinity of the contact between the old Castle Peak dome and the new dome. Rockfalls on the southern flank of the dome has now begun to deposit material into the old July 28 vent.

EDM measurement were carried out on the eastern triangle to Castle Peak and southern triangle to Chances Peak today. The data is currently being processed. No GPS measurements were made today due to continued problems with the equipment.

FTIR measurements were made directly to the dome for the first time today. The measurements were made from the school yard at Harris Village. COSPEC measurements were made along the southern main road between Plymouth and St Patricks. The results from both measurements are currently being processed.

Samples were collected today of the 12 May pyroclastic flow deposit in the Tar River Valley.

The present level of activity at the Soufriere Hills Volcano continues to cause concern to the scientists. The MVO urges that visits to the evacuated zone are kept to a minimum. The Tar River, Long Ground and Whites areas are extremely dangerous and should not be entered under any circumstances.

Montserrat Volcano Observatory