Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 15 October
to 16:00 16 October 1996
The current alert level is AMBER

Activity at the volcano has remained at about the same level as yesterday. There have been several long-period earthquakes and rockfalls. Limited views of the crater area have confirmed that the October 1 dome is still growing.

The seismicity has been varied during the last 24 hours, with five long-period earthquakes, seven rockfall signals and three volcano-tectonic earthquakes. Two of the long-period earthquakes were quite large, and were followed by rockfall signals. These events are thought to be small explosions from the dome. One event, at 14:51 today, coincided with a small rockfall from the dome which was recorded by the CCTV camera on Perches Mountain.

Two of the volcano-tectonic earthquakes were located at depths of 2 to 3 km beneath the crater. The third VT earthquake occurred at a depth of about 15 km, about 4 km east of the crater. Such earthquakes are rare, but are to be expected occasionally around the volcano.

Visibility has been poor today, and only limited views of the October 1 dome were possible. It was confirmed that dome growth is continuing. The small spine seen recently has disappeared, and the slopes of the dome are still quite gentle.

The sulphur dioxide readings taken on October 14 were analysed today, and showed an average of about 650 tonnes.

Measurements of the underwater shape of the delta were made this morning from the Police launch.

The seismic activity and continued dome growth observed today indicate that the volcano remains in an active and highly dangerous state. Further activity, possibly leading to an explosive eruption, could occur with little warning. 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