Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 01 June
to 16:00 02 June 1996

Volcanic activity at the Soufriere Hills volcano has remained at a moderate to high level, dominated by rockfalls, small ash clouds and repetitive hybrid seismic events.

Seismicity has been dominated by the occurrence of repetitive hybrid events and moderate-sized rockfall signals. Exact counts of these are not yet available, but the numbers are similar to yesterday. The hybrid seismic events continue to occur at the same rate as yesterday afternoon - about one every 1.5 to 2 minutes throughout the reporting period. The amplitude of these events is variable. Rockfall events appear to have declined slightly in amplitude and in number during the day. The largest of these were at 22:20 on 1 June and 00:56 and 06:45 on 2 June; the first one was of a size commonly associated with small pyroclastic flows down the Tar River valley.

There were a few long-period events and no VT earthquakes recorded during the reporting period. Intermittent low-amplitude broadband tremor has been recorded on the stations nearest the crater since about 03:00 on 2 June.

Viewing conditions have been poor throughout the day and only brief glimpses were obtained of the lower flanks of the dome. There is a new small whaleback'-shaped feature on the eastern flank of the dome, just to the north of Castle Rock. This feature is quite similar in morphology to other whaleback features which developed during late January in the northern and southeastern parts of the dome. The largest ash column observed during this reporting period was at 07:34 on 2 June and rose to about 5,000 ft above sea level. Smaller ash clouds were seen during the rest of the day, drifting on the prevailing light winds to the west over the Gages and Upper Amersham areas and producing light ashfall at times.

Low cloud cover prevented attempts to measure the Eastern EDM Triangle to Castle Peak. No GPS measurements were made today due technical problems.

Measurements of gas concentrations at ground level were made today in the Amersham area using the FTIR technique. COSPEC measurements of SO2 gas concentration in the volcanic plume were made along the coastal road in Plymouth. The results of these measurements indicate an SO2 flux of 193 tonnes per day.

The current volcanic activity at the Soufriere Hills volcano remains highly dangerous. The MVO therefore 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