Significant amount of gas and steam at White Island volcano, New Zealand

Active vents at White Island/Whakaari volcano in New Zealand are emitting substantial steam and gas plumes. The Volcanic Alert Level remains at 2 and the Aviation Color Code at Yellow.

Observation and gas flights on March 2 and March 9, 2023, confirmed that the volcano continues to emit significant amounts of steam and gas.

The temperature of the steam and gas was measured at around 240 °C (464 °F), considerably lower than the temperatures recorded in the past, which were over 600 °C (1 112 °F). Despite the lower temperature, the visible plumes generated by the steam can be substantial and are visible from the mainland during specific weather patterns, as happened on March 5, 2023.¹

Although gas fluxes have increased compared to previous measurements, they remain within the usual range for White Island. No signs of volcanic ash or other eruptive activity were observed during the recent flights.

The substantial amounts of rain during the past month have led to an increase in water levels in the crater lake and some of the smaller pools. As a result, some fumaroles are now underwater, leading to geysering and bubbling.

The Volcanic Alert Level remains at 2 (moderate to heightened unrest), and the Aviation Color Code remains at Yellow, acknowledging the current level of activity but also recognizing the greater level of uncertainty due to the current lack of consistent, useful real-time data.

Additional gas and observation flights to the island will be undertaken as weather permits, until the on-island equipment and power supplies can be serviced. The intermittent access to webcam images from the island provides some level of visual monitoring between the flights.

It is important to note that the Volcanic Alert Level reflects the current level of volcanic unrest or activity and is not a forecast of future activity. While Volcanic Alert Level 2 is mostly associated with volcanic unrest hazards, including the discharge of steam and hot volcanic gases, earthquakes, landslides, and hydrothermal activity, the potential for eruption hazards still exists, and eruptions can occur with little or no warning.

Geological summary

Uninhabited 2 x 2.4 km (1.2 x 1.5 miles) White Island, one of New Zealand’s most active volcanoes, is the emergent summit of a 16 x 18 km (10 x 11.2 miles) submarine volcano in the Bay of Plenty about 50 km (31 miles) offshore of North Island.

The island consists of two overlapping andesitic-to-dacitic stratovolcanoes; the summit crater appears to be breached to the SE, because the shoreline corresponds to the level of several notches in the SE crater wall. Volckner Rocks, four sea stacks that are remnants of a lava dome, lie 5 km (3.1 miles) NNE.

Intermittent moderate phreatomagmatic and strombolian eruptions have occurred throughout the short historical period beginning in 1826, but its activity also forms a prominent part of Maori legends.

Formation of many new vents during the 19^th and 20^th centuries has produced rapid changes in crater floor topography. The collapse of the crater wall in 1914 produced a debris avalanche that buried buildings and workers at a sulfur-mining project.²

References:

¹ Whakaari/White Island continues to emit significant amounts of gas and steam. Volcanic Alert Level remains at Level 2 – GeoNet – March 10, 2022

² White Island – Geological summary – GVP