Montserrat Volcano Observatory

Morning Update
Report for the period 16:00 12 September
to 07:00 13 September 1996

Activity at the Soufriere Hills volcano has continued at about the same level seen during the previous reporting period. However, unlike during the past several days, no volcano-tectonic earthquake sequence occurred. Small- to moderate-sized rockfalls from the flanks of the growing lava dome dominated the activity. A few large rockfalls which occurred, for example on at 16:42 yesterday 12 September, led to the generation of small pyroclastic flows and associated ash clouds. Light ashfall from the 16:42 event was registered in Gages, Lovers Lane and Richmond Hill. Several small long-period events were also recorded. Tremor recorded at the seismic stations closest to the Crater was broadband and intermittent in nature.

Visibility during the early morning was very poor because of the low cloud cover.

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