Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 26 September
to 7 am 27 September 1997

The sequence of explosive eruptions has continued overnight, with a further explosion at 00:01 local time. Subsequent pyroclastic flows are thought to have travelled down Gages, however, it is not known as yet if material entered any other valleys around the volcano. This should be clarified by today's visual observations.

In the few hours leading up to the explosion, there were some isolated hybrid earthquakes but these events did not constitute a swarm. Again, loud, roaring noise was heard as the volcano erupted. This did not continue for as long as some of the previous eruptions. A volcanic tremor signal, measured on the seismic network, went on for about 30 minutes after the explosion. After this the volcano was quiet, with only a few small rockfall signals being recorded on the seismic network.

The eruption column swiftly rose to estimated heights of above 10,000 feet. Light pumice fall was reported by MVO observers in Old Towne, closely followed by ash fall in Salem and other areas. At 00:25 lapilli fell at the MVO at Mongo Hill. However, wind directions were more easterly than the previous 24 hours and the north part of Montserrat was less severely affected by fallout.

Further explosions are very likely and these could be bigger than those experienced in the last few days. Pyroclastic flows are likely to reach the Belham valley and an event directed down the Belham valley of a similar size to the one on Sunday morning, which destroyed the airport, would reach the Belham bridge and impact upon Friths 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