Jul 5 2006, 2:00 pm - Raoul Island Volcano

Hydrothermal activity (upwelling and bubbling of springs) continues in the Green Lake crater area at Raoul Island.

This is sufficient to maintain the Scientific Alert Level at Alert Level 1 (some signs of unrest).

The volcano-hydrothermal system at Raoul Island continues to be weakly active following the eruption in March 2006. Hydrothermal activity (upwelling and bubbling of springs) continues in the Green Lake crater area, although it is confined to vents formed in March. A thermal infra-red image obtained from a satellite on April 11 indicated a lake temperature of 39.2°C, which is about 7°C warmer than the average April temperature. Following the March eruption the water level in Green Lake rose several metres and drowned many of the new vents. The level of the lake is continuing to fall slowly, but is still above the pre-eruption level.

Hot springs which reach the sea at Oneraki Beach on the north shore of the island increased in area following the eruption, but the temperature did not change from the 70-75°C normally measured there. The area of the springs has not returned to that before the eruption.

Earthquake activity close to Raoul Island declined following the eruption, but in recent weeks earthquakes within 30 to 40 km of Raoul Island have been slightly higher than is typical.

Steven Sherburn
Duty Volcanologist