Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 26 October
to 16:00 27 October 1996
The current alert level is AMBER

The seismic activity at the volcano has decreased since 21:18 last night with the end of the of the volcano-tectonic earthquake swarm. A few small to moderate-sized rockfalls have been recorded during the day and some brief views were obtained of the crater.

The volcano-tectonic earthquake swarmwhich began at 03:00 yesterday continued up until 21:18 last night. A total of 84 VT earthquakes were recorded with 19 eventsrecorded during the current reporting period. Most of the earthquakes were located under the crater at depths of less than 2 km. Four rockfalls were recorded during the period. The largest event occurred at 11:19 and produced a small ash cloud which drifted towards the west. A single regional earthquake was recorded at 12:35 today.

Despite generally poor viewing conditions for most of the day, some brief views were obtained of the crater area. The eastern part of the October 1 dome is now visible from Windy Hill and Farrells to the north of the volcano. Observations from the helicopter indicate that the deposits in the Tar River Valley has undergone some significant change due to recent heavy rainfall. The central canyon leading east from the scar at the top of the valley has been extensively eroded into a U-shaped valley.

Measurement of line lengths on the northern triangle and between the road at Farrells and upper Farrells were conducted with the Total Station today. Line length between Windy Hill - Farrells and St Georges Hill - Farrells lengthened by 12.5 mm and 3 mm respectively since these were last measured on 21 October. Additional measurements would have to be made on the road to Farrells - upper Farrells line before any comparisons can be made since this is the first time that atmospheric corrections have been used on this line.

COSPEC measurements were conducted along the west coast road today. The data is currently being processed and will reported in tomorrow's report.

The volcano remains in an active and highly dangerous state. Further activity, possibly leading to an explosive event could occur with little warning in the near future. Everyone who enters the evacuated zone must remain alert and be ready to move at short notice. Individuals who go beyond the Long Ground area into the Tar River valley are risking death.

Dr Simon Young of the British Geological Survey returned to Montserrat today after a 3 week visit to the United Kingdom.

Montserrat Volcano Observatory