Montserrat Volcano Observatory

Daily Report
Report for the period 16:00 10 February
to 16:00 11 February 1997
The current alert level is ORANGE

Activity at the Soufriere Hills volcano has been at a slightly higher level than it has been over the past four days. The style of eruption remained about the same, with most of the events occurring in sequences in close succession to each other, and the volcano remaining fairly quiet for the rest of the time during the reporting period.

Another periodic swarm of volcano-tectonic earthquakes, the most dominant feature of the volcanic activity in recent months, occurred between 2:00 am and 7:00 am this morning. This swarm was more intense than any of the last 5 that occurred in the almost daily sequence and was also mixed with hybrid earthquakes. Between 9:00 and 10:00 am an episode of low level volcanic tremor followed the swarm. A total of 69 volcano tectonic earthquakes and 35 hybrid earthquakes were recorded, along with 22 isolated rockfall signals. Two long period earthquakes were also recorded. Apart from the VT swarm and subsequent tremor volcano has been quiet for most other times.

For most of the morning, observers from Whites witnessed small pyroclastic flows from the dome. While the tremor was in progress small continuous rockfall activity and small ash clouds were seen coming from the most active area. Visibility was limited to brief glimpses of the dome but from all indications, its appearance was much like yesterday. The south-west part of the new extrusion with large blocks showed little evidence of movement.

The cracks on Chances Peak were measured today, the first time in 14 days. Since the time the larger crack was last measured it extended laterally by 17 inches to a width of 41 inches. It also extended dextrally (along its length) by 9.4 inches The net rate of lateral extension moved up from 0.7 to1.2 inches per day over 14 days.

Despite the low level of activity, the eastern face of the dome is steep, and is likely to undergo further collapse. Any collapses are likely to be gradual, and follow the recent pattern. However, larger and more violent collapses can not be ruled out. Residents are therefore reminded to remain alert and responsible at all times. This includes traveling with protective gears such as ash masks at all times, spending the minimum possible time in the evacuated zones and being prepared to take recommended action when advised. Zone E, which includes Cork Hill and the airport, remains safe. The Tar River Valley and the upper Galway's area are very dangerous.

Montserrat Volcano Observatory