Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 14 May
to 16:00 15 May 1996

Activity at the Soufriere Hills Volcano has not changed much since the latter part of yesterday. Seismicity is still dominated by small- to moderate-sized rockfalls.. These were often associated with small ash clouds which were blown on the wind towards the west, depositing ash in Plymouth and surrounding areas. The largest rockfalls were at 05:20, 07:51 and 12:52 on 15 May. There were sixteen long period events and two VTs during this period, a level of activity very similar to yesterday. Both VTs were located slightly north of the Soufriere Hills Volcano at depths of about 1 km. There have been a few small hybrid events recorded since about 02:00 on 15 May.

Visibility throughout most of the day was generally poor, with low cloud cover obscuring the volcano. Brief views were obtained of the lower parts of the dome from several places around the volcano. Most of the rockfalls appear to originate from the northeastern part of the dome, although there was one on the western flank at around 12:00 on 15 May. Moderate steam emissions were observed from the base of the northern flank of the dome. Blue smoke was observed near the upper Tar River Valley area. This might have been generated by a small bush fire.

Low cloud cover once again prevented completion of measurements along the Eastern EDM triangle - only one measurement was made today. GPS measurements were conducted on both the MVO and University of Puerto Rico networks. The ashfalls on Sunday damaged one of the processing computers used in the MVO GPS network - this has caused some delay in processing of the data.

Further COSPEC measurements were made today and the data is still being processed. The results from yesterdays measurements are less than 50 tonnes per day, consistent with the low measurements obtained since the COSPEC programme was restarted last month. Tests of the FTIR gas-measurement equipment were carried out this afternoon and the first results should be obtained as soon as the dome becomes visible.

Residents of areas which continue to be affected by recent ashfalls are again advised to wear dust masks when working in these areas. More ashfalls from rockfalls and possible pyroclastic flows in the Tar River Valley area should be expected. The areas affected would depend mainly on the prevailing wind direction.

Dr William Ambeh left Montserrat this morning after a two month tour of duty. Richard Robertson takes over the role of Chief Scientist and Head of the MVO.

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