Government Information Service

The Volcanic Explanation
For The 24 Hour Period Ending 4 PM On Friday July 25, 1997
A Presentation Of The Government Information Services
In Conjunction With The MVO.

The alert level system has been revised by zones.

The dome was viewed very briefly today at lunchtime. The time was too short to take any measurements or see where the latest growth is. Rockfalls and small pyroclastic flows continue to be the main activity at the Soufriere Hills Volcano.

115 rockfalls, one long-period event and one volcano-tectonic earthquake were recorded today. The rockfall count is much higher than yesterday. Again low amplitude broadband tremor was recorded at St. George's Hill for most of the day.

Another new triangle was set up on the western side of the volcano between Garibaldi Hill, Lees Yard and the MVO for EDM Measurements (Electronic Distance Measurement). This will be used to check the deformation.

The dome is continuing its growth and large pyroclastic flows onto all sides of the volcano remain a strong possibility. Recent pyroclastic flows and ash eruptions have occurred with no direct association to seismicity. Mudflows may occur in the Belham River Valley after heavy rainfall. These mudflows are very hot move rapidly and can go further than pyroclastic surges. No one should try to handle or walk on these deposits, they are unstable and retain heat for many weeks. Dust masks should be worn when ash is in the air.

Dr. Maggie Mangan (US Geological Survey, Hawaii Volcano Observatory) and Mr. Rob Watts (Independent) left Montserrat after tours of duty.

Government Information Service