Montserrat Volcano Observatory

Daily Report
Report for the period 5 p.m. 12 October
to 5 p.m. 13 October 1998

Activity increased earlier today with a collapse of material from the northern part of the dome. This caused pyroclastic flows in two of the valley which surround the volcano and ashfalls on the western side of the island.

A total of 13 rockfalls, 2 long period earthquake and 15 volcano-tectonic earthquakes were recorded on the broadband seismic network. Most of the volcano-tectonic earthquakes occurred in the 10 hour period leading up to a collapse of the dome which occurred at 0801 local time. The collapse caused pyroclastic flows which went into Tuitts Ghaut and Tyers Ghaut. The flow in Tyers Ghaut extended to within 200 meters of the Molyneux road while the flow in Tuitts Ghaut reached Paradise Estate.

Volcanic tremor was recorded after the collapse and lasted for the remainder of the reporting period. This tremor was correlated with vigorous ash venting from high up on the northern flank of the dome and was similar to that observed earlier in the month.

Observations from the ground and helicopter indicate that the ash cloud associated with collapse event reached up to 25,000 feet. The cloud drifted towards the northwest and deposited ash in areas extending from Woodlands to Weekes with most of the ash falling over Cork Hill, Old Towne, Olveston, Salem and the Belham Valley. Ashfall was also reported on Nevis.

Residents of Montserrat should continue to check Radio ZJB in case of sudden developments in the state of the volcano.

Montserrat Volcano Observatory