Government Information Service

The Volcanic Explanation
For The 24 Hour Period Ending 7 AM On Saturday January 11, 1997
A Presentation Of The Government Information Services
In Conjunction With The MVO.

Over the last 24 hours the October 1st dome (dome # 2) at the Soufriere Hills Volcano has become more unstable with continuing rockfalls and pyroclastic flows. Although activity decreased slightly overnight it is still continuing this morning (Saturday).

Over the reporting period over 130 rockfalls have occurred together with a number of hybrid and long period earthquakes, the majority of these are at shallow depths below the crater.

For most of yesterday (Friday) the visibility was good and scientists observed that at least one of this week's pyroclastic flows has reached the sea. There has been heavy erosion of the area around Castle Peak and the peak looks entirely different to what it did just a month ago. Scientists also observed new growth on the northwestern side of the dome.

The pyroclastic flow activity has produced ashclouds clearly visible to all in Montserrat, they have reached heights of between 4000 and 6000 feet. The ash has been blown westwards and has dropped in Plymouth.

Yeterday (Friday) scientists and MVO staff collected samples of airborne dust particles in the Plymouth area and have sent them to England for analysis. COSPEC measurements to see the amount of gas in the atmosphere were also taken and gave a result of 390 tonnes per day, a decrease over yesterday.

Gravity, GPS and EDM measurements were all taken over the last 24 hours but the ash in the atmosphere prevented proper results for the latter.

Because of overnight rain the area around the dome this morning is very steamy so no good views are visible as we write this, however conditions are expected to clear up later.

The alert level remains at ORANGE, however residents are being urged to keep tuned to Radio ZJB for up to the minute updates in case a change is necessary. For readers overseas, the siren system is now in place and is tested on a weekly basis. If there is a change in the alert stage, the sirens sound and this basically tells everyone to tune into their radios for the information.

Government Information Service