Montserrat Volcano Observatory

Morning Report
Report for the period 4 pm 8 July
to 7 am 9 July 1997

The alert level system has been revised by zones

Volcanic activity since yesterday continued the cyclic pattern established several weeks ago. A low amplitude peak in the tiltmeter cycle culminated in an extended period of ash generation starting at 5.15 am and continuing at the time of reporting. This was not preceded by any increase in seismic activity, except for the occurrence of several large rockfall signals. The ash cloud from this episode reached over 10,000 feet and sped rapidly westwards in the strong winds.

A mudflow also occurred last night between about 7.10 pm and 7.30 pm during a heavy rain storm. A peak on the seismic records during the mudflow could have been due to small pyroclastic flows, and light ash fall was reported in Olveston several minutes later. During the rain storm, the wind was directed to the north and some residents to the north of the island reported sulphurous odours. This episode occurred in the trough of the tiltmeter cycles and emphasises that activity can increase rapidly at any time.

People are reminded that mudflows can be extremely hot if recent deposits are remobilised by heavy rain. The current area of activity in the crater makes Mosquito Ghaut and Gages the most likely pathways for pyroclastic flows and surges, but further flows in Tuitt's or Tar River are possible. The Belham River valley is also dangerous and should not be entered. Access to Plymouth is completely restricted, and people should stay completely away from the flanks of the volcano. Everyone should continue to stay alert, and listen to Radio Montserrat for any announcements.

Montserrat Volcano Observatory