Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 30 August
to 7 am 31 August 1997

Activity at the volcano was quieter overnight. Seismic records have been dominated by rockfall and small pyroclastic flow signals and very small hybrid. The intense pyroclastic flow activity of yesterday was waning at the beginning of this reporting period and weak ash emissions were observed in the late afternoon and early evening. Enhanced rockfall activity started to pick up about 1.30 am and there were several large rockfall signals for a period of about two and a half hours, gradually dying down at 4 am. Minor rockfall events have continued since then. There is a pattern of peaks in activity beginning roughly every 12-16 hours. Currently the summit of the volcano is shrouded in cloud.

The pyroclastic flow activity of yesterday afternoon has produced further significant changes on the northern flanks of the volcano. Mosquito Ghaut was filled almost completely and an erosion gully was cut in the flow deposits immediately beneath the active dome. This new channel fed pyroclastic flows in the late afternoon across the Farrels Plain to the north-west rather down the infilled Mosquito Ghaut. Larger flows may thus extend into the Belham Valley by this route or by flowing down the Gages valley and around St Georges Hill.

Explosions may take place with little or no warning and may be more intense and longer lasting than those which occurred earlier this month. If an explosion does occur, small rocks and ash can be expected to fall everywhere on the island. People should seek shelter under a strong roof and wear a helmet or other head protection. Ash and falling rocks make driving hazardous. Ash will be present in the atmosphere and masks should be worn outdoors.

Pyroclastic flows are expected on all flanks of the volcano, and it is never safe to enter the exclusion zone, including the Belham river valley. Access to the exclusion zone is completely restricted. Access to areas south of the Nantes River is allowed during the day, but only for essential visits. Everyone should remain vigilant and listen to Radio Montserrat.

Montserrat Volcano Observatory