Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 12 October
to 4 pm 13 October 1997

There have been three explosive eruptions during the reporting period, with ash fall and pyroclastic flows associated with each one. Although the size of each explosion is relatively constant, the interval between explosions is very variable at the moment.

Explosions occurred at 10:24 last night, at 9:32 this morning and at 3:25 this afternoon. Due to low cloud throughout the day, visual observations of the ash columns was limited, but all three columns are thought to have got above 15,000 feet. No clasts fell out on inhabited areas of Montserrat, but ash fall was widespread, though generally light. Winds at upper levels were to the north and north-east whilst the lower level winds carried ash from the pyroclastic flows towards the north-west.

Pyroclastic flows from the three explosions travelled down all of the ghauts leading from the volcano. The most notable flow was during this morning's explosion, when a large, very fast-moving flow travelled down White River to the sea, inundating the O'Garra's area and destroying the Radio Antilles installation. Other notable flows occurred in Tyer's Ghaut during last night's explosion and in the Gages valley down towards the southern end of Lover's Lane.

Venting of steam and ash followed each explosion, accompanied as usual by seismic tremor. Some lightening and thunder was associated with each eruption cloud.

A total of 6 hybrid earthquakes, 5 vts, 4 long-period events and 4 rockfalls were recorded on the seismic network during the reporting period. This continues the generally low level of seismic activity seen during most of the current explosive phase.

Preliminary air quality monitoring has been started by MVO this week and results will be published in the evening report each day.

More explosions are expected and it is always possible that the next one will go on for longer than those previously experienced. If an explosion were considerably longer lasting than those already seen then it would be followed by bigger pyroclastic flows and surges. Material would then be expected to get further down Tyer's Ghaut and into the Belham River and all residents still remaining in Friths, Old Towne and Salem are urged to move out as soon as possible.

After explosions, fallout can occur anywhere on the island and hard hats or other suitable protection should be worn outside. If possible, close shutters and stay indoors until the fallout is over. Driving during ash or pumice fall is dangerous and should be avoided if possible. When driving on ashy roads drive slowly, particularly near pedestrians and allow plenty of time for your 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