Volcanic activity

There have been nineteen rockfall signals, three long-period, two volcano tectonic and one hybrid earthquake recorded this week.

Minor degradation of the lava dome continues with occasional small pyroclastic flows. Most of these have travelled down the Gages valley to the west, however a few have occurred on the eastern side in the Tar River. Good views from the helicopter this week have shown that there are two clear chutes of fresh rockfall and pyroclastic flow debris at the head of the Gages valley and a that the Tar River flows were sourced from the large vertical face on the south-eastern side. The maximum runout of the pyroclastic flows was around 1.5 km and ash clouds associated with them were very weakly convective rising to only a few hundred meters.

The average SO2 measurement for eight days between the 17 and 25 August is 303 tons per day, with a maximum of 515 and a minimum of 162 tons per day. Strong sulphurous smells on the morning of the 27 August were due to the southerly winds blowing the gas plume over inhabited areas of Montserrat.

The Hazard Level is 3. There is no access to the terrestrial Zone C and daytime transit access to shipping through the maritime extension of the zone.

Additional information on the Soufrière Hills Volcano, the Hazard Level System and a glossary of volcanic terms can be found at can be found at the MVO website: www.mvo.ms.

There have been twenty nine rockfall signals, four long-period, one volcano tectonic and one hybrid earthquake recorded this week.

A number of small to moderate rockfalls and pyroclastic flows have occurred this week, most of which have been sourced from the western side of the lava dome and traveled down the Gages valley. The maximum runout of these pyroclastic flows was around 2 kilometers and the ash clouds associated with them were only weakly convective. Some of these flows were probably triggered by heavy rainfall.

Clear views of the volcano on the afternoon of 19 August showed that there have been no significant changes to the lava dome.

The average SO2 measurement for a ten day period from 5 to 16 August is 396 tons per day, with a maximum of 1153 and a minimum of 221 tons per day.

A small lahar was formed in the Belham valley associated with intense rainfall on 19 August.

The Hazard Level is 3. There is no access to the terrestrial Zone C and daytime transit access to shipping through the maritime extension of the zone.

Additional information on the Soufrière Hills Volcano, the Hazard Level System and a glossary of volcanic terms can be found at can be found at the MVO website: www.mvo.ms.

Activity at the Soufrière Hills Volcano has continued to be low this week.

There have been twenty-seven rockfall signals, two long-period, five volcano tectonic and two hybrid earthquakes recorded this week.

Reasonably clear conditions for most of the week allowed observation of mild ash and steam venting and slightly increased rockfall activity. Most of the activity was focused in the collapse scar and above the Gages valley.

On Friday 6 August at 4:21 pm a small ash plume rose to about 1000 feet above the dome. It was not clear whether this was due to a single ash venting pulse or a large rock fall into the collapse scar on the dome. On Sunday 8 August at 5:10 am a pyroclastic flow went into the Gages valley.

Helicopter observations and ground based observations during the week indicate that there are no significant changes in the dome.

No SO2 figures are available at the time of reporting.

The Hazard Level is 3. There is no access to the terrestrial Zone C and daytime transit access to shipping through the maritime extension of the zone.

There have been six rockfall signals, two long-period, four hybrid and two volcano tectonic earthquakes recorded this week.

Overcast weather conditions for most of the week prevented any clear observations of the dome.
The average sulphur dioxide flux for seven days this week was 232 tons per day, with a minimum of 173 and a maximum of 393.

The Hazard Level is 3. There is no access to the terrestrial Zone C and daytime transit access to shipping through the maritime extension of the zone.