Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 on 14 November
to 16:00 on 15 November 1995

The rate of occurrence of earthquakes under the volcano has increased significantly over the past several days. So far, only one hundred and fifty seven (157) selected earthquakes have been located today. These events occurred during the period up to 09:00 on November 15. The data recorded after 9:00 a.m. are still being processed. The earthquake depths were all in the range 0-3 km (approximately zero to two miles). Almost all of the events were concentrated beneath the Soufriere Hills Volcano. The nature of the events is similar to the series of earthquakes that accompanied the doming episode in mid to late September, and similar surface manifestations could occur during the next several days.

Two eruptions were observed, one at 16:10 yesterday and the other between 9:00 and 10:00 a.m today. Small ash clouds were observed from both eruptions. The eruptions lasted for longer but were less intense than previous events, hence the absence of major ash falls.

The Tar River, O'Garra's and Gallway's EDM lines were measured today. The Tar River line continues to shorten but the rate has decreased compared with that of the previous few days. There is as yet insufficient data to draw any conclusions from the other two lines, although no significant shortening has occurred.

GPS (Global Positioning System) measurements were carried out overnight for the first time since October 30. This monitoring technique measures the distance between points across the volcano. Scientists surveyed three points which define the lines between Tar River and St. George's Hill, Tar River and Reed's Hill and St. George's Hill and Reed's Hill. The preliminary results show that the distances between the points have changed very little, indicating that there has not been any major swelling of the volcano.

This and other deformation data suggest that if an intrusion has or is occurring it is not large.

Montserrat Volcano Observatory