Montserrat Volcano Observatory

Daily Report
Report for the period 6 pm 11 January
to 6 pm 12 January 1998

Seismic activity at the volcano today was very similar to that experienced yesterday. Between 16:00 yesterday and 16:00 today there were 16 hybrid earthquakes, 39 rockfall signals, 4 long-period earthquakes and 8 volcano-tectonic earthquakes. The cyclicity of recent days has broken down somewhat, although there are still distinct peaks in the RSAM record which correlate with enhanced rockfall and small pyroclastic flow activity.

Visibility was very good for a short period this afternoon and theodolite measurements were taken on the western and northern flanks of the dome. A brief helicopter flight around the southwest of the volcano revealed glimpses into the collapse scar from the Boxing Day event, where a new dome with a steep front face and extensive talus slope has grown. The size of this new dome could not be ascertained as the flight was curtailed by ash in the air.

Yesterday's GPS survey revealed no significant movement of the Lees Yard pin. An EDM survey was also undertaken today and the results should be available tomorrow.

The clearer weather today showed that the volcano was continuously venting ash and steam, especially in the middle of the afternoon, with the top of the vertical column reaching 8 to 10,000 feet. Rockfalls and small pyroclastic flows were mainly occurring in the upper part of the White River, but some flows were also seen down the Tar River valley.

Dust levels at all monitoring stations across the island were low today, although there was a little more ash in the atmosphere today due to the drier conditions.

People should remain alert and listen to Radio Montserrat for further information.

Montserrat Volcano Observatory