Montserrat Volcano Observatory

Morning Update
Report for the period 16:00 13 September
to 07:00 14 September 1996

Volcanic activity overnight has been at about the same level as that observed yesterday. Small- to moderate-sized rockfalls remain the dominant seismic signal recorded by instruments on the volcano. The largest rockfall occurred at 16:39 on 13 September; no ashfalls were reported from this event. Low-amplitude broadband tremor which was recorded for most of the period reduced from 01:50 early this morning. The size and number of rockfalls also reduced from about this time. There were two periods during which swarms of volcano-tectonic events occurred; between 20:08 and 22:00 on 13 September and beginning at 06:20 this morning. This sequence is at present continuing. A few small long period events were also recorded during the period.

Visibility during the early morning was poor due to low cloud cover at the volcano.

Further rockfalls and pyroclastic flows will occur but all indications at the moment are that the pyroclastic flows will be confined to the Tar River Valley area. However, areas affected by associated ashfalls will obviously depend on the direction and strength of the wind at the time. The rainfall overnight has made roads very slippery so extreme care should be taken when driving in affected areas. Dust masks should be worn at all times in ashy environments.

The Tar River Valley and surrounding areas are extremely hazardous and should not be entered under any circumstances.

Montserrat Volcano Observatory