Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 10 December
to 16:00 11 December 1996
The current alert level is ORANGE

The volcano remains very dangerous, with the continuation of the volcano-tectonic earthquake swarm that restarted two days ago. Galway's Wall continues to show signs of being very unstable, with large blocks of rock falling from it and more cracks appearing. The wall could collapse at any time, and trigger a lateral blast. The areas designated as zone A/B in the temporary risk map are extremely dangerous, as a lateral blast may cause pyroclastic flows and surges in any direction. In the very worst case, such surges could affect the top of St Georges Hill, and that area, or any other part of zone C/D, should not be occupied at night. Residents of zone E must remain alert, as the conditions could change suddenly and require the evacuation of zone E. At this time, the scientists are confident that zone E remains safe.

A total of 101 VT earthquakes were recorded during the last 24 hours. This represents a reduction in the total number of earthquakes from yesterday, although seismic activity is still at an extremely high level. The largest earthquakes today are still about the same size as the largest earthquakes in the previous swarm. All the earthquakes were located at shallow depths beneath the crater.

Five landslides from the Galways Wall were detected by the seismic network during the last 24 hours. Most of these slides were from the lower eastern part of the wall and some were witnessed by the team at the Galway's Observation Post.

Helicopter inspections were made of the Galway's Wall this morning and afternoon. Cracks on the wall continue to appear, and some indications of bulging were seen in the form of peeling off of slabs of rock.

No views of the dome were possible due to low cloud.

The EDM measurements from late yesterday afternoon suggest a continuation of the trend of shortening of about 1 cm per day which started several weeks ago. Attempts to measure both the eastern and northern triangles were thwarted by low cloud today.

Work was almost completed on the installation of the CCTV camera at the Galway's Observation Post. Once telemetry is in place on Bransby Point, the signal should be reaching the observatory.

Dr Barry Voight left Montserrat after a nine day visit to help in the assessment of the Galway's Wall.

Montserrat Volcano Observatory