Science Alert Bulletin - White Island & Ruapehu

GNS have issued a new Science Alert Bulletin for White Island. No change in alert level though. Read the bulletin here.

GNS have also issued a new SAB for Ruapehu. No change in alert level. The bulletin is not yet on the GNS site but reads as follows...

GNS scientists are continuing to monitor Ruapehu. Elevated gas output and high lake temperatures continue, while volcanic tremor has declined. Unrest continues at Ruapehu and it remains unclear if this is a sign of further eruptions. The volcano last erupted on 25^th September 2007.The Alert Level remains at Level 1.

Ongoing monitoring at Ruapehu, including a Crater Lake visit to measure the lake temperature and collect water samples, data from airborne gas measurements and seismic activity have continued to show variations. The airborne gas plume measurements show the SO₂ emission has gradually increased since last year’s eruption and the CO₂ flux has varied. The emission rates of both SO₂ and CO₂ gases, have shown significant increases since April 2008, being about ten times above the typical background. Our latest measurements on June 12 remains high. The Crater Lake temperature has remained elevated and fluctuates between 34 and 37° C. The latest measurement was 35.2° C (12 June). Sustained heat from depth is required to keep the temperature this high, for this length of time. It is believed that the source of this heat is magma within the volcano conduit. This magma is also producing the higher than normal gas flow and other chemical changes in the lake. The slight increase in the background level of volcanic tremor we previously reported has now declined to typical background levels. These observations remain consistent with the volcano-hydrothermal system responding to recent eruptions and ongoing interaction with magma in the volcano conduit. The volcano remains in a state of unrest and the possibility of further activity remains at the volcano. If further eruptions occur, they may occur without warning. The Alert Level remains at Level 1 (Departure from typical background surface activity, signs of unrest) and will continue to be re-assessed regularly.