Activity at the Soufriere Hills volcano during this reporting period has continued at a low level and visibility remains poor so that no new views of the crater area have been obtained.
Fifty four rockfalls were recorded during the reporting period, an increase from yesterday. Most of these were small and resulted from the continued stabilisation of the walls of the scar feature. The largest rockfalls were at 07:46 and 09:43 this morning (23 September). Eleven hybrid events were recorded by the seismic network; no VTs or long-period events were recorded however. Broadband tremor was recorded at a low amplitude on the Gages seismometer throughout the reporting period.
Visibility was very poor all day and no views of the dome or scar were obtained.
The GPS survey started on Saturday was completed today and results are being processed. A second occupation of the new network will be required before any changes in line lengths can be documented. No EDM measurements were made due to low cloud.
The COSPEC machine remains under repair in Canada but is expected to be returned early next week.
An air and particle sampling network was initiated today by Dr Peter Baxter and Andy Nichol, both from the UK. This sampling will enable better characterisation of the ash and assessment of its health impacts.
MVO scientists are expecting more rockfalls and possibly pyroclastic flows to occur during the next few days as the unstable sides of the new scar feature at English's Crater stabilise. All indications are that the rockfalls and pyroclastic flows will be confined to the Tar River valley area. Dust masks should be worn at all times in ashy environments, which may persist for some time as ash dries out and blows around. Drivers should exercise caution and consideration for other road users, especially when driving through areas still affected by ash or gravel.
The extensive damage which occurred in the Long Ground area last week demonstrates the extreme danger which individuals subject themselves to if they venture into this area or beyond into the Tar River valley. The Tar River and Long Ground areas are now extremely hazardous and we urge individuals who persist in ignoring this advice to think very seriously before making trips to these potentially deadly zones.