During a GeoNet gas flight on Wednesday, a significant rise in SO2 emissions from the new active vent was detected, compared to the last gas flight on July 18th.
Small amounts of ash were also observed in the plume downwind of the island. The gas and ash are being released from the vent measuring approximately 10–15 meters in diameter. These findings align with satellite data from the Wellington Volcanic Ash Advisory Centre (NZ MetService) and observations from GeoNet webcams in Whakatāne and Te Kaha.
The GeoNet continue: We were also able to obtain a small ash sample during the flight and initial analyses are consistent with it been derived from a shallow magma source. These new data confirm there has been a change in the eruptive activity from the island since the beginning of August. There is more gas, and more continuous minor entrainment of volcanic ash in the hot plume. This is consistent with magma (molten rock) being close to the surface and driving the activity. This is part of the typical eruptive cycles seen at Whakaari/White Island. Based on past eruptive episodes over the past 30 years, this activity could continue for some time, maybe weeks to months.
NZ MetService has been able to track the volcanic ash in the plume for tens of kilometres from the island over the past week due to clear sky conditions around Whakaari/White Island. Plumes have reached up to 2 kilometres elevation, under calm conditions.
The concentrations of volcanic ash are very low and sometimes difficult to detect. As the weather changes the plume may at times be blown towards the Bay of Plenty coast. However, at the current level of ash emission, there is a very low likelihood of ash impacting the mainland. The level of volcanic activity would have to change significantly for this likelihood to increase.
Source: Geonet New Zealand volcano activity update 16 August 2024