Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 22 October
to 16:00 23 October 1996
The current alert level is AMBER

The level of volcanic activity has been low during the past 24 hours. Good visibility has allowed the viewing of several moderate-sized rockfalls from the October 1 dome, which have produced small ash clouds. The seismicity has been dominated by rockfalls, with very few other seismic signals recorded.

There were eleven rockfalls signals today, a slight decrease in numbers since yesterday. Most of the rockfalls occurred during the night. Six volcano-tectonic earthquakes were recorded between 2200 last night and 0200 this morning. These were located at shallow depths beneath the crater.

There have been good viewing conditions today, and observations of the volcano have been possible from the east. The October 1 dome is now visible from Farrell's. Many small rockfalls were observed from the eastern face of the dome, and a small spine collapse was noted at 13:06 today. A new growth was seen on the south side of the eastern face of the dome.

COSPEC measurements were carried out today to measure the levels of sulphur dioxide coming from the volcano. There was a small problem with the instrument, and so the results are not yet available.

EDM measurements were carried out on the eastern triangle today. The measurements made yesterday on this triangle showed a small shortening in line lengths of 3-4 mm since the measurements of 19 October. There has been essentially no change in the lines since yesterday. Yesterday's measurements of the western triangle showed a shortening of 7 mm in the Amersham to Chances Steps since the line was last measured on 26 September.

A helicopter survey of the new dome is currently under way. The data collected will be used to calculate the volume of the dome, and when this is compared to past measurements, will allow the rate of dome growth to be calculated. These data take several days to process, and will be reported as soon as they are available,

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.

Montserrat Volcano Observatory