Government Information Service

The Volcanic Explanation
For The 96 Hour Period Ending Easter Weekend,
7 AM On Tuesday April 01, 1997
A Presentation Of The Government Information Services
In Conjunction With The MVO.

The current alert level is ORANGE

Over the Easter weekend there was a dramatic increase in activity at the Soufriere Hills Volcano causing the alert level to be increased.

There were major pyroclastic flows from the dome down the Tar River Valley in the east and the White River Valley in the South. The White River Valley Flow over the Galways Wall has covered Galways Soufriere and there is no longer a valley where this used to be. The material is now level to the roundabout where cars used to be parked. In addition further down the River the Great Alps Waterfall has also been filled in.

Overall the White River Valley flow travelled 3.6 kilometres and finished just a few metres from the sea close to O'Garro's. It is estimated that there was about 1 million cubic metres of material in this flow and it gauged a chunk out of Galways Wall some 40 metres deep.

The flows down the Tar River valley reached about 50 metres from the delta at the base of the valley.

Ash clouds reached 10,000 feet and huge amounts of ash have been dumped in Plymouth and points south. There were light ashfalls in Corkhill, Isles Bay Hill, Old Towne, Salem and Olveston. Scientists are warning of the dangers of ash and are asking everyone to wear their dust masks. Scientists on Easter Monday measured the levels of ash in Plymouth and reported that it was 15 mm thick in some places.

Residents of Richmond Hill were advised on Easter Monday to move to safer areas and this means that there should now be no nightime occupancy of Zones A, B, C, and D. Drivers heading for the airport have been advised to drive the northern route and not to use the Central Corridor.

Seismic activity continued over the weekend with volcano-tectonic, hybrid and long period earthquakes all being recorded including some in the early hours of this morning (Tuesday). The dominant signals for the weekend have however, been rockfalls and pyroclastic flows.

There were some COSPEC measurements taken in the early part of the weekend to check the sulphur dioxide gas levels in the atmosphere, results show low levels of about 160 tonnes per day.

The weekend's heightened activity is the result of dome growth of the southern part of the dome adjacent to the Galways Wall and shows that pyroclastic flows can occur at any time. It is important that everyone remains vigilant and keeps tuned to ZJB for further updates.

Government Information Service