Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 19 December
to 6 pm 20 December 1997

The volcanic activity has been about the same level today, with rockfall signals once again being the predominant seismic triggers.

The broadband seismic system is now back in action, and it recorded 96 rockfall signals, 18 hybrid and 18 long period earthquakes between 16:00 yesterday and 16:00 today. One of the hybrids and one of the long period events preceded rockfall signals. There were no volcano-tectonic earthquakes today.

Heavy rain and cloud today prevented any good views of the dome, but the seismic activity suggests that growth continues over the Galways flank of the volcano. Some periods of low amplitude tremor was recorded at the seismic stations and may be a result of small mudflows or steaming.

Air quality at all monitoring stations across the island is good today.

Although activity is mainly focused in the southern central part of the volcano, the area of growth on the dome can change very quickly. Growth activity appears now to be backing up behind the major build-up of material in Galways, and a renewal of rockfalls or pyroclastic flows down Gages or Tar River would not be a surprise in the near future.

Today, Dr. Richard Luckett from the British Geological Survey returned to the island after a short visit to a conference in San Francisco.

Montserrat Volcano Observatory