Volcanic activity overnight reached the highest level yet during the current eruption of the Soufriere Hills volcano. Continuation of pyroclastic flow generation from dome collapse up until about 20:30 last night (17 September) was followed by a brief period of lower activity before an abrupt, small explosive eruption occurred at about 23:42 local time (03:45 ZULU). This explosive event lasted for about 48 minutes, with saturation on all stations for this period. Since that time, activity has returned to a background level, with just a few small rockfalls and volcano-tectonic earthquakes being recorded.
Reports and visual observations by MVO staff through the night suggested that an eruption column was sustained for some short period of time, depositing gravel-sized material of both pumiceous and dense nature in areas across the central corridor and in the Richmond Hill and Foxes Bay areas. All ash erupted during the night, either from the pyroclastic flows or from the explosive phase, was blown westwards over Plymouth and Richmond Hill, and both of these areas received very heavy ashfall.
Overnight observations of burning property in the Long Ground area were confirmed during a helicopter flight at daybreak this morning. These properties were set alight by large hot blocks of dome rock which were blasted eastwards from the summit dome. This blasted material covers the areas west of Long Ground into the Hermitage area, but is not present on any of the other flanks of the volcano. More than half of the houses in Long Ground were impacted by blocks falling through roofs, but this damage appears to be confined to this area only. The Tar River Estate House has been partially destroyed by a pyroclastic flow.
Although no clear views of the dome area have yet been obtained, it appears that the major collapse scar is on the eastern flank of the dome, with the scar cutting deep into the old Castle Peak Dome. Some material has been eroded from Castle Peak also. The delta at the mouth of the Tar River valley has been enlarged again, and the valley itself is now totally devoid of vegetation.
A meeting of the Volcano Management Committee takes place at 08:00 today and a press release will be issued following that meeting dealing with administrative issues.