Government Information Service

The Volcanic Explanation
For The 24 Hour Period Ending 7 AM On Saturday April 12, 1997
A Presentation Of The Government Information Services
In Conjunction With The MVO.

The current alert level is ORANGE

The activity at the Soufriere Hills Volcano was elevated yesterday with near continuous pyroclastic flows. The alert level was raised to ORANGE yesterday afternoon.

The low amplitude tremor which began at 9:42 am increased and near continuous pyroclastic flows occurred between 11:00 am and 12:17 pm. The seismic signals reached the maximum recording on several of the seismometers. The activity was greater than on Easter weekend, but not as high as September 17, 1996. No precursory signals were evident and by lunchtime the activity had dropped to background levels.

There were a total of 5 volcano-tectonic and 5 long period earthquakes with 32 rockfalls during the day yesterday (Friday). The ashclouds rose to between 7,000 to 10,000 ft during the rockfall activity. Good views of the White River valley were seen from the helicopter, but the dome was covered by low clouds. The pyroclastic flows traveled further down the White River and some burning trees were seen.

A shallow earthquake swarm started at 3:20 am today (Saturday) and is ongoing at the time of this report. The size of the earthquakes is similar to previous swarms.

A GPS survey and COSPEC measurements were taken yesterday and the results will be available soon.

The visibility was not good early this morning but should improve during the day, so the scientists can evaluate the state of the dome following yesterdays activity.

The volcano remains active and dangerous, with a very large dome which could collapse at any time. People should exercise extreme caution and remain vigilant at all times. Ash levels are high and everyone is urged to wear their dust masks in ashy areas.

Government Information Service