"It is early days in our scientific investigation of these developments, but the geyser has clearly entered phase two of its recovery. In the first phase, which started 18 months ago, she attained a level of overflow and started regaining some heat, but it was not hot enough to prompt an eruption.
"Over the past 18 months she has obviously pumped out the cold water and started hitting temperatures that allow for an eruption. We will be collecting water samples to confirm any changes in the water to support these observations."
Mr Scott said Papakura had had average temperatures around mid-90C during the past 18 months, but an initial reading on Thursday of 100.9C was a significant increase.
"Papakura is not yet erupting as strongly as she was in the 1970s and '80s, but it's a great start."
Papakura Geyser and its activity can be clearly and safely seen from existing visitor pathways and viewing areas.
