Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 16 September
to 7 am 17 September 1997

The level of volcanic activity was moderate overnight. A period of elevated rockfall activity which began late yesterday afternoon developed into sustained pyroclastic flow activity between about 10pm and midnight. The level of rockfall activity decreased after midnight.

The pyroclastic flows probably travelled down Mosquito ghaut and onto Farrell's plain but no actual observations of the flows were possible last night.

There were several hybrid, long period and volcano-tectonic earthquakes overnight but once again there was no distinct earthquake pattern and they did not occur in swarms. One or two of these isolated events were quite sizeable.

The level of activity has been elevated for several days now, and larger collapses can be expected. The timing and size of these collapses is impossible to predict, but large pyroclatic flows could travel far down the Belham Valley as far as the sea. Residents of the exclusion zone south of Nantes River are thus urged to move north, as pyroclastic flows in the Belham Valley could produce surges threatening the Friths, Old Towne, Olveston and Salem areas.

Large collapse espisodes have in the past lead to explosive activity at the volcano, and residents are reminded that ash and rocks could fall anywhere on the island during such activity. If an explosion occurs, stay indoors under a strong part of the roof. All Montserratians are advised to keep listening to Radio Montserrat for updates on the situation.

Montserrat Volcano Observatory