Steam-driven activity at White Island increasing as rising crater lake drowns active vents, New Zealand

Small, muddy, geyser-like explosions are taking place in the active crater at Whakaari/White Island volcano over the past three weeks, GNS Science reported on September 26, 2019. The explosions are occurring due to a rising crater lake drowning the active vents.

GNS Duty Volcanologist Steve Sherburn said steams reached up to 10 m (32.8 feet). "They do not pose any hazard to visitors to the island and are not a sign of increasing volcanic activity," Sherburn said. "Normally the gas and steam would vent directly to the atmosphere, now it’s through the water in the vents and is visible as the geyser-like activity."

The crater lake level has been rising since early-August. The rising lake level has impacted the surface activity around the active vents on the west side of the crater floor. Geysering-type activity has become established in the main active vent due to hot steam and gas passing through the now drowned active vent area. 

Volcanologist Brad Scott further explained the rise of the crater lake, saying "one is climate and rainfall, and we've had a lot of rainfall lately. The second is volcanic gas and steam coming into the volcano and being condensed and turned back from the vapor phase into water. It's a combination of those two."

GNS Science and the National Geohazards Monitoring Center are closely monitoring the island for probable activity signs.

"We'd have to see monitored parameters indicative of change and unrest- that may be a change in the amount of gas coming out, the type of gas coming out, a change in the seismic activity, a change in the temperature of the lake," Scott added.

"There's a whole pile of different parameters that we monitor, and we'd have to see two or three of those parameters changing and indicating an increase in volcanic unrest – and we're not seeing that at the moment."

White Island is one of New Zealand's most active volcanic zones. The last eruption occurred in April 2016.

Featured image credit: GNS Science