Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 on 22 November
to 16:00 on 23 November 1995

Thirty two (32) earthquakes have been located during this period. The seismicity continues to be scattered along the regional zone of weakness which runs across the island between Roche's Yard and Garibaldi Hill, with events concentrated at depths of 0 to 3 km beneath St George's Hill, Soufriere Hills and South Soufriere Hills/Roche's Yard. After a relatively quiet period during the evening of 22 Nov, volcano-tectonic earthquakes became more common over night and, since about 13:00 on 23 Nov, a period of broadband tremor has been recorded at the Gages station; this broadband tremor continues to the present time.

Due to the low level cloud which covered the flanks of the volcano all day, only one set of EDM lines was measured today. The Farrells lines from Windy Hill and the main road both showed very minor shortening, continuing the trend that has been seen on these lines throughout the period of measurement. Attempts will be made to measure all of the other EDM lines tomorrow.

GPS (Global Positioning System) surveys continue to be carried out each day. Processing of the results has been hindered today due to minor technical problems; results from the previous several days will be reported tomorrow.

Visual observations were attempted from the rim of English's Crater today, but the low cloud cover presented any sighting of the active areas within the crater. However, considerable rock breaking and small landslides were heard from around the area of recent doming which indicates continued growth of this feature. The presence of Carbon Dioxide was sensed in the summit area for the first time today. This gas can be toxic so casual visitors to the summit are advised that such practices are dangerous.

Dr Peter Baxter, a British expert on the health impacts of volcanic eruptions, arrives on island this evening to advise the government and health workers on matters concerning the ongoing volcanic activity here on Montserrat.

Note: Processing of earthquake locations for the period 16:00 on 19 Nov to 16:00 on 20 Nov has been completed; a total of 286 earthquakes were located for this period, occurring in the depth range 0 to 2.5 km (0 to 1.5 miles) beneath the Soufriere Hills volcano.

Montserrat Volcano Observatory