Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 3 October
to 4 pm 4 October 1997

There has been one explosion in the last 24 hours, otherwise there has been little seismic activity.

The explosion occurred at 8:33 this morning and was followed by pyroclastic flows down Tuitt's, Gages, the Tar River Valley and Tyers Ghaut. The flow down Tuitt's was later found to have reached the sea just South of the airport, flows in other directions were relatively small. As usual for these events there was a period of ash venting after the explosion that correlated with tremor recorded by the seismic networks. The ash from this mornings explosion reached 18,000 feet and blew West and Northwest, dropping ash on Salem but no further North.

8 hybrids, 10 volcano-tectonic earthquakes, 4 long period earthquakes and 5 rockfall signals triggered the seismic network over the reporting period. There were no seismic precursors to the explosion but a few hybrids dir ectly afterwards, while the tremor was also being recorded. The dome was very clear today and the crater was observed to be slightly bigger than when previously seen. There was vigorous fumarolic activity from the crater for much of the day. A helicopter trip was made to sample material from this mornings flow near the airport.

There is a good chance of more explosions and these could be larger than anything seen so far. The resulting pyroclastic flows could very easily reach the Belham valley and surges could travel up the valley sides for a considerable distance. All those remaining in the exclusion zone are urged to leave. If the sirens sound in this area at any time, people should move north immediately.

After an explosion fallout can occur anywhere on the island. People should shelter in a strong building and wait for the fallout to end. If you do have to move about then head protection should be worn. Falling ash and pumice reduces visibility and makes driving conditions extremely hazardous. Roads remain difficult and plenty of time should be allowed for any journey. 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