Risk assessment maps released by GNS Science show Whakaari/White Island's crater floor remains a highly dangerous zone, another eruption looking increasingly likely due to the volcano's "highly volatile" status.
Volcanic geologist Graham Leonard revealed the maps during Thursday afternoon's National Emergency Management Agency (NEMA) media briefing.
Leonard reiterated that Whakaari/White Island "remains highly volatile and uncertain".
"Our experts estimate the likelihood of an eruption has moved to 50 to 60 percent in the next 24 hours - up from 40 to 60 percent yesterday," he said.
"There is an ongoing, consistent trend in increasing tremor... this has contributed to an increase in the likelihood of eruption estimates each day. Today is less safe than yesterday and the day before."
One map shows White Island's most up-to-date risk zones as of December 12, while a second map shows the last pre-eruption calculation for Whakaari, made by GNS on December 2.
The shaded areas indicate fatality risk decreasing as distance from the crater increases.
The risk assessment map from 10 days ago has a light yellow shaded area around its crater, indicating "access with appropriate workplan and permissions".
On Thursday's map, a sizeable area around White Island's crater is a red "no-go" zone. The middle area of the volcano, a yellow zone, indicates accessibility in "exceptional circumstances". The base and surrounding water has been labelled as safe to access with an "appropriate workplan and permissions".
"These zones are based on the likelihood of eruption that I just gave you. The risk increases towards the crater and decreases out to sea," Leonard said.
"Effectively, the red zone is a no-go for GNS staff and the other zones would [only be accessible] with special approval. As scientists, we need a strong reason to enter the yellow zones. Police make their own decisions. We have shared our risk assessment with the police.
"These zones are dynamic, as the status of the volcano is highly volatile and uncertain... these maps are being updated daily."
Leonard said the area affected by Monday's eruption is not dissimilar to the red zone indicated on the map.
He reiterated the risk estimates and their corresponding zones can change very rapidly.
"This level of volcanic activity is the highest we've seen since the eruption in 2016.
"GNS Science is providing a constant stream of information to the emergency response agencies and the public and will update this forecast tomorrow - or sooner if there is a dramatic change."
