Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 29 September
to 7 am 30 September 1997

Since 4pm yesterday afternoon there have been three further explosive events at the volcano. The explosions occurred at 4:48 pm and 9:53 pm yesterday evening (September 29) and 4:44 am this morning (September 30). These have been the 21st, 22nd and 23rd explosions in this current phase which began on September 22. The time interval between explosions has now shortened to an average of five and a half hours for the last 4 explosions.

The first explosion at 4:48 pm was heard at the Observatory on Mongo Hill. Pumice flows from this event entered the Tar River Valley, Tuitt's Ghaut, upper Tyer's Ghaut and White River. A diffuse plume spread toward the west at low levels and toward the east at higher levels. Ash and steam venting continued for over an hour after the main pulse. There were no reports of fall-out in any occupied areas of Montserrat.

The second event at 9:53 pm was quickly accompanied by lightening which develops from the rapidly rising plume. The plume rose to above 10,000 feet where it stalled and was then carried slowly northward by the upper level winds. A period of ash and steam venting again followed the main pulse of activity.

The latest explosive event from the Soufriere Hills Volcano occurred at 4:44 am this morning. The plume was carried westward at low levels over Plymouth. At approximately 7000 feet altitude the plume began to spread out and extended toward the north-west forming an umbrella cloud. Above this level the upper parts of the plume were carried toward the north-east by the high level winds. Observations of the volcano shortly after this event indicated that very little material came over the northern crater wall. There was considerable amounts ash drifting westward over Plymouth suggesting that any pumice flows may have entered Gages Valley and White River. This will hopefully be clarified later in the day. No fall-out was reported from any occupied areas of Montserrat. A short period of ash and steam venting followed the main part of the explosion.

Overnight there has been a number of volcano-tectonic and hybrid earthquakes recorded by the seismic networks.

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