Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 27 September
to 7 am 28 September 1997

The sequence of explosive eruptions continued late yesterday and this morning, with further explosions at 17:15 pm yesterday and at 4:28 this morning. These explosions were similar in style to those of the rest of the week, producing pyroclastic flows in valleys around the volcano and some fallout, although due to the wind direction, very little fallout was on areas of Montserrat still inhabited.

The explosion late yesterday afternoon was not preceded by any earthquake activity. Pyroclastic flows travelled down Tuitt's and Tyer's ghauts and in the Gages valley. The ash column rose to over 25,000 ft and drifted north and then east but appeared quite dilute and no ash or pumice fell on central or northern Montserrat. A brief glimpse through cloud during a subsequent observations flight offered views into the explosion crater to a depth of around 100 metres (300 ft) as steam and ash continued to pulse from the crater.

This morning's explosion was preceded by hybrid earthquakes, and contained an extended explosive signal on the seismic network. The eruption column rose rapidly to at least 10,000 ft and again spread slowly northwards. The lower level ash generated from pyroclastic flows was blown westwards. Again, there was no reported ash or pumice fallout on central or northern Montserrat.

Both explosions were followed by vigorous ash and steam venting accompanied by a strong roaring sound. Lightening and thunder was also seen and heard in the eruption column.

Further explosions are very likely and these could be bigger than those experienced in the last few days. Pyroclastic flows could reach the Belham valley and an event directed down the Belham valley of a similar size to the one last Sunday morning, which destroyed the airport, would reach the Belham bridge and impact upon Frith and Salem. All those remaining in the exclusion zone are urged to leave as soon as possible.

When explosions happen fallout may occur anywhere on the island, so hard hats or other suitable protection should be worn. Preferably, people should seek shelter in a sturdy building and wait for the fallout to end rather than trying to move or drive anywhere during the fallout period. Falling ash and pumice reduces visibility and makes driving conditions extremely hazardous. The pumice and coarse ash deposited over the previous few days has made many roads very treacherous. Plenty of time should be allowed for any journey and drivers should be very careful. The wearing of ash masks is recommended at all times. Everyone is advised to keep listening to Radio Montserrat for information on the activity.

Montserrat Volcano Observatory