Montserrat Volcano Observatory

Morning Report
Report for the period 8 pm 03 August
to 7 am 04 August 1997

Activity at the volcano overnight has remained at a very high level with a hybrid swarm and continued pyroclastic flow and rockfall activity. A hybrid earthquake swarm this morning was followed by an explosion and pyroclastic flows at just after 6:30 am.

The major pyroclastic flow activity of yesterday evening continued until after 7:30 pm. This was followed by small pyroclastic flows and rockfalls throughout the night. A moderate pyroclastic flow occurred at just after 2 am in the middle of the tiltmeter cycle. This emphasises that pyroclastic flows can occur at any time.

A hybrid earthquake swarm started at just after 4 am and continued until after 6 am. This was followed by a very intense period of pyroclastic flow and ash generation activity at 6:30 am. Loud rumbling was heard from the volcano at this time and rock fragments up to 5 mm diameter rained down on the Observatory. This was probably a result of an explosion from the dome.

The activity is still generally following a cyclical pattern in the tiltmeter with regular inflation and deflation of the volcano corresponding to the earthquake swarms and continuous pyroclastic flows respectively. However, pyroclastic flows have also occurred outside the most probable time period, and so at no time is it safe to enter the exclusion zone, including the Belham river valley.

There is ash in the air in the west of Montserrat and therefore dust masks should always be worn in these areas. Drivers should also be considerate whilst driving in ashy conditions. The Belham River valley is very dangerous and should not be entered. Access to the exclusion zone is completely restricted, and people should stay completely away from all the flanks of the volcano. Everyone should continue to stay alert, and listen to Radio Montserrat for any announcements.

Montserrat Volcano Observatory