Montserrat Volcano Observatory

Morning Report
Report for the period 16:00 3 December
to 07:00 4 December 1996
The current alert level is ORANGE

The activity at the volcano has continued to increase slowly overnight, with the intense swarm of VT earthquakes continuing. The situation is extremely serious. The Galway's Wall is unstable and collapse may be imminent, leading to a lateral blast. For this reason, absolutely no access to zones A, B, C and D is permitted until further notice. A lateral blast could affect any part of these zones, and occur with very little warning.

About 180 earthquakes have been recorded since 4 pm yesterday. This means that the rate of earthquakes is more than ten per hour, the highest rate recorded in this swarm. Almost 800 earthquakes have occurred since 30 November, and this is the largest earthquake swarm recorded since the eruption began in July 1995. All the earthquakes are at shallow depths beneath the crater, and are thought to be due to magma pressurisation. The increasing numbers and size of the earthquakes indicates that the pressure is still increasing, and this makes the Galway's Wall more likely to fail.

Visibility is very good this morning and MVO staff will continue their inspections of Galway's Wall and the dome. We plan to install further monitoring equipment close to the Galway's Wall.

Dr Barry Voight and Prof Steve Sparks will give a public lecture at the Vue Pointe Hotel on Thursday at 7:30 pm. Everyone is invited.

The siren system will be tested between 3 pm and 6 pm today. This test takes place every Wednesday.

Montserrat Volcano Observatory