Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 3 November
to 6 pm 4 November 1997

Activity at the volcano has been at a high level today with a substantial dome collapse down the White River Valley. The hybrid earthquake swarm finally came to an end after 50 hours.

There has again been steam and ash venting from the dome today although early in the day it was noticeably less vigorous than on previous days. Fumaroles on the northern face of the new 22 October dome were rather more vigorous than on previous days. Small pyroclastic flows and rockfalls were observed in the White River Valley at regular intervals throughout the morning. At 12:06pm a large dense ash cloud rose to about 10,000ft above the volcano as a series of pyroclastic flows were generated, mostly from the new October 22 dome, and travelled down the White River Valley. The flows reached the sea and the surge component of the flows travelled several tens of metres beyond the delta at O'Garro's. The dome collapse was continuous for about 70 minutes and it is estimated that about 2 million cubic metres of material was removed from the dome. The pyroclastic flows ceased at about 12:50pm.

Following the collapse, venting from the Galways part of the new dome was vigorous and had a strong pulsing nature, each pulse coming at about 15 second intervals. This venting continued for about an hour.

There has been one hybrid swarm during the reporting period which started at 10:30 am on the 2nd November and came to an end early this afternoon after about 50 hours. There was a brief lull in hybrid earthquakes between 2.30 and 3.30am this morning but the swarm rapidly regained its previous intensity and was accompanied by tremor for several hours. Hybrid swarms are commonly followed by a period of enhanced pyroclastic flow activity as occurred today. Individual earthquakes were still large and similar in size to those at the start of the swarm.

The MVO considers that the volcano is currently in an extremely dangerous state and more explosions or pyroclastic flows could occur at any time. Areas such as the Belham valley, around Trants and the airport are under a very real threat of being impacted by large pyroclastic flows. Under no circumstances, even for brief periods, should anyone be visiting these areas. Friths, Old Towne and Salem are not safe and anyone remaining in these areas is strongly urged to move out of the exclusion zone. In the event of an explosion residents should take shelter indoors under a strong roof and avoid driving. Make sure you always have an ash mask to hand because a change in wind direction could bring ash into the inhabited parts of the island at any time. At the present time ash levels in the air remain low. Stay tuned to Radio Montserrat for further information.

Montserrat Volcano Observatory