Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 5 September
to 7 am 6 September 1997

The level of activity at the volcano was relatively low overnight. Seismic activity was dominated by rockfall signals and very small hybrid earthquakes that sometimes merge into continuous low-level tremor. There were also a few small long-period earthquakes. Small peaks in the earthquake activity still appear to be regularly spaced, with the current interval about 10 hours.

The dome is visible this morning, and is venting a moderate amount of ash. There were some excellent viewing conditions during the night when the dome was seen clearly from the Observatory. Rockfall activity was taking place over much of the north and west flanks of the dome. The activity appeared to be more concentrated above Gages Valley and Mosquito Ghaut. Small rockfall activity was almost continuous and shows that the dome continues to grow at a fast rate, underlining the potential dangers from it.

Explosions may take place with little or no warning and may be more intense and longer lasting than those which occurred at the beginning of August. 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. The size of the dome and the recent filling up of Mosquito Ghaut and the upper parts of Gages by pyroclastic flows make it more likely that large pyroclastic flows can enter the Belham Valley.

Access to the exclusion zone, south of the Nantes River, is now completely restricted. Everyone should remain vigilant and listen to Radio Montserrat.

Montserrat Volcano Observatory