Montserrat Volcano Observatory

Daily Report
Report for the period 4 pm 1 July
to 4 pm 2 July 1997
The current alert level is ORANGE

Volcanic activity has been lower today with a continuation of the cyclic pattern but at less intensity than over the previous few days. Two more episodes of enhanced activity and deformation have occurred, but only one period of significant pyroclastic flows.

Activity at the volcano increased gradually after 4 pm yesterday, and a moderate but prolonged ash eruption started at about 6.30 pm. This lasted almost two hours and produced an ash cloud which rose quite slowly to over 20,000ft, and pyroclastic flows into Mosquito Ghaut and Fort Ghaut. Those in Mosquito Ghaut reached down as far as Harris's, but the run-out of flows in Fort Ghaut could not be seen through the thick ash and the gathering dusk. An inspection of the area this morning revealed that the end of the flow had reached down Fort Ghaut to level with the Catholic Church opposite Jubilee Town.

A further period of ash eruption and pyroclastic flow generation occurred at 9.25 am with pyroclastic flows down Mosquito Ghaut and Fort Ghaut. The upper reaches of the Gages Valley are now full of debris and therefore future pyroclastic flows could travel to the north of St. Georges Hill towards Lees.

The tiltmeter shows a continuation of the same pattern, although the time between periods of higher activity has been longer today. In total, only 72 rockfall signals and 47 hybrid earthquakes were recorded by the seismic network today. No long period or volcano-tectonic events were recorded.

A small pyroclastic flow down Mosquito Ghaut also occurred at 11.57 am this morning, and was outside the period when flows are expected. So it is emphasised that pyroclastic flows can occur at any time.

It seems likely that the cyclic nature of the activity will continue with repeated periods of pyroclastic flows giving rise to ash clouds away from the volcano, and thus people in the safe zones should stay alert and listen to Radio Montserrat. The pyroclastic flows may travel further than before. The current area of pyroclastic flow activity makes Mosquito Ghaut and Gages the most likely pathways, but further flows in Tuitt's, Tar River or White River are probable as well. Much of Mosquito Ghaut and Fort Ghaut are filled with material which will enable the surge component of any flow to spread more easily over a larger area. Access to Plymouth is completely restricted. Zones A and B are extremely dangerous and nobody should go into these areas at all.

The Belham River valley is very dangerous. It may provide a pathway for further pyroclastic surges and there is also a risk of hot mudflows which may form rapidly if there is a period of heavy rain. Mudflows travel extremely fast and may be near boiling point, they may extend much further along the Belham River valley than the pyroclastic surges.

The pyroclastic flow and surge deposits will remain extremely hot for several days. Residents must not approach, attempt to handle or walk on the deposits because of the risk of severe burning.

There is likely to be some re-suspension of ash in the air today especially if it does not rain. Residents and workers are urged to wear a dust mask.

The airport is closed today and will remain closed until further notice.

Montserrat Volcano Observatory