Government Information Service

The Volcanic Explanation
For The 24 Hour Period Ending 6 PM On Wednesday December 18, 1996
A Presentation Of The Government Information Services
In Conjunction With The MVO.

The activity at the Soufriere Hills Volcano can be described as moderate today (Wednesday). The new dome (dome # 3) continues to grow and generate rockfalls into the upper Tar River Valley. These have caused some ash clouds which drifted westwards. Scientists are warning of possible pyroclastic flows into the Tar River Valley area putting Long Ground at further risk.

Early this morning there was a helicopter inspection of the Galways Wall however visibilty was pretty poor so not much was seen. There did not seem to be much activity but the wall continues to deform although not as quickly as in the past.

The level of seismicity was low over the last 24 hours with no volcano-tectonic earthquakes and just two small longer period events being recorded. However, there were 17 dome rockfalls recorded by the seismic network.

Some EDM measurements were taken today. This entails bouncing a beam of light off a reflector on the mountainside. Results show that the lines to Castle Peak have shortened a little since they were last measured. When lines shorten it shows that the slope being measured is bulging outwards a little.

A new piece of measuring equipment was installed today at Whites. The "continuous recording gravity meter" will show if there is continuous swelling and help scientists to understand the nature of that swelling.

The sirens were tested this afternoon and were found to be in good working order. The alert stage remains at ORANGE and at this level there should be no one living in Zones A,B,C, and D on the December revised risk map. E mail subscribers can drop me an E mail requesting this map and if they give us their mailing address we will mail them a copy.

Government Information Service