A series of short-lived, low-energy steam explosions have occurred on Whakaari/White Island today.
The explosions took place over about 100 minutes following a small increase in volcanic tremor levels, GNS Science said in a statement.
The Volcanic Alert Level remains at 1.
GNS Science volcanologist Brad Scott said the small events did not appear to have produced any traces of ash locally and, since the event, activity had returned to a low level.
"Starting at around 2.20am today our seismic and acoustic [air pressure] sensors at Whakaari/White Island detected a series of small steam explosions.
"No observations were available from the island's webcams as it was still dark. The overall series of pulses lasted for about 100 minutes and were of a similar size to those recorded on December 29, 2020," Scott said.
"Volcanic tremor levels started to rise around 9pm yesterday and stopped around 5.50am today coincident with the end of the explosions."
Sudden, small steam explosions can occur with little or no warning.
Scott said a gas flight was completed yesterday and showed no changes in gas
flux or crater conditions from a month earlier. The level of seismic tremor had
been slightly above background in the two days preceding the explosions but has
since returned to background levels.