Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 29 June
to 7 am 30 June 1997
The current alert level is ORANGE

Volcanic activity has been elevated overnight with a continuation of the hybrid swarm which began yesterday afternoon, several pulses of pyroclastic flow activity and a repeat of the tiltmeter cycles.

The hybrid swarm that started yesterday afternoon at 2 pm continued until about 8 pm last night. The swarm consisted of many small events interspersed with larger hybrids. The end of the swarm coincided with a drop in the tiltmeter readings. Several small pyroclastic flows then occurred between 9 pm and 10:30 pm down Mosquito Ghaut and into Fort Ghaut.

This cycle was repeated at 2:15 am with a resumption of hybrid earthquake activity. This second swarm was less intense and of shorter duration than the previous swarm with fewer and smaller events being recorded, but this was followed by major pyroclastic flow activity from 4:45 am until the time of reporting. The activity is now less intense than when it started. The eruption column reached approximately 15000 feet, and drifted to the west over Plymouth. A helicopter from HMS Liverpool reported minor pyroclastic flows down Mosquito Ghaut after 6 am, but most of the activity appeared to be down the Gages valley towards Plymouth. Again the end of hybrid activity and start of pyroclastic flow activity was marked by a decrease in tiltmeter readings.

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 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 a risk of hot mudflows in some of the ghauts if heavy rain falls, and these would be extremely dangerous for anyone caught in their path.

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 current area of pyroclastic flow activity makes Mosquito Ghaut and Gages the most likely pathways, but further flows in Tuitt's or Tar River are probable as well. The Belham River valley is also extremely dangerous and should not be entered. Access to Plymouth is completely restricted. Zones A and B are extremely dangerous and nobody should go into these areas at all.

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

Montserrat Volcano Observatory