Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 13 August
to 7 am 14 August 1997

Activity at the volcano has remained at a high level with continuing hybrid swarms and pyroclastic flows. The hybrid swarm which began at 1830 12/8/97 finally stopped at 0030 last night. The swarm consisted of well over 800 events.

The recent hybrid earthquake swarms are thought to be associated with rapid extrusion of new dome material. This is supported by visual observations of the dome yesterday morning which indicated that a large spine has been extruded in the crater area. Further brief views this morning showed that there is a new cluster of spines above the Gages wall area. A further hybrid earthquake swarm began again this morning at 0630. The intensity of this swarm has so far been much less than the previous swarm.

At 0538 a pyroclastic flow down the Gages valley was observed from the MVO. This was estimated to have reached the lower soufriere area. Given the new growth of material on the dome, more pyroclastic flows in this area are probable.

Further explosions may take place with little or no warning. These may be more intense and longer lasting than those already experienced. If explosions do occur, the central zone should be evacuated immediately and people in the northern zone should seek shelter under as strong a roof as possible. After an explosion small rocks and ash can be expected to fall everywhere on the island. Ash and falling rocks make driving hazardous. Ash is present in the atmosphere and masks should be worn outdoors.

Pyroclastic flows are expected on all flanks of the volcano, and so at no time is it safe to enter the exclusion zone, including the Belham river valley. Access to the exclusion zone is completely restricted. The central zone is evacuated over night and people should not return to their homes until advised to do so. Everyone should remain vigilant and continue to listen to Radio Montserrat for any announcements.

Montserrat Volcano Observatory