“The second of those eruptions deposited ash close to the island over the short period of the eruption,” she said.
MetService meteorologists reported that no volcanic ash was detected in the plumes using satellite imagery, but sulphur dioxide was detected.
Short-lived increases in degassing or steam may generate plumes of gas, possibly containing minor amounts of volcanic ash, with little or no warning over the coming days.
The volcanic alert will remain at level 3 while the Earth Sciences NZ Volcano Monitoring Group continues monitoring Whakaari for any changes in activity. 
The alert system is a scale from zero to six, with level 3 indicating a minor volcanic eruption.
There were currently no sensors installed on the island, and scientists relied on remote cameras, satellite data, periodic observation and gas measurement flights to track any developments, Mazot said.
Earth Sciences NZ would provide updates as new information became available.
Whakaari, 48km off the North Island coast, is one of New Zealand’s most active volcanoes.
The last previous eruption activity was observed on August 28, coating the island in a thin covering of ash. The activity settled quickly.
Yesterday’s eruptions came amid an ongoing inquest into the deadly eruption on December 9, 2019, which killed 22 people.