Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 20 December
to 6 pm 21 December 1997

The volcanic activity has been about the same level today, with rockfall signals once again being the predominant seismic triggers. The broad band system triggered 30 hybrid earthquakes, 20 LP earthquakes, 73 rockfalls and 1 volcano-tectonic earthquake.

Cloud today prevented views of the dome, but the seismic activity suggests that growth continues over the Galways flank of the volcano. A small pyroclastic flow was observed down the Tar River in the afternoon. Small mudflows occurred overnight and have blocked roads within the exclusion zone. A survey of the ash distribution from the explosive activity in September and October began today.

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.

Montserrat Volcano Observatory