Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 25 October
to 16:00 26 October 1996
The current alert level is AMBER

The seismic activity at the volcano has increased markedly since 03:00 this morning. A swarm of volcanic earthquakes started then, and has continued until the end of the reporting period. There have also been a few moderate-sized rockfalls. Low cloud has been present for most of the day, and so only a brief view of the crater was possible.

The volcano-tectonic earthquake swarm began at 03:00, and 65 VT earthquakes have been recorded since then. The swarm is still continuing. Most of the earthquakes have been large enough to locate, and have been at shallow depth beneath the crater. Similar swarms of earthquakes were recorded in August and September, and are thought to be related to magma movement close to the surface of the volcano. There were five rockfall signals, and most of these occurred before the start of the swarm.

A moderate regional earthquake was recorded at 21:58 last night, and there was a flash flood in Fort Ghaut between 13:24 and 13:38 this afternoon.

The viewing conditions have been very poor today, and only one brief view of the October 1 dome was possible. No major changes in the dome were seen, although it appears to be slightly bigger than when it was last sighted. No EDM measurements were possible because of the low cloud.

Four COSPEC runs were carried out this morning to measure the levels of sulphur dioxide gas from the volcano. The results show an average flux of 290 tonnes/day, much lower than recent measurements. This low result may be partly due to the weather conditions today.

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