Whakatāne, Kawerau rattled by series of earthquakes

Geonet's "felt report" showing where and how strong people felt a 4.1m quake in Whakatane and surrounding areas last night. Photo / Geonet

A "swarm" of earthquakes near Whakatāne rattled towns in the Bay of Plenty last night, the largest a 4.1-magnitude quake.

The 4.1-magnitude event struck shortly after 11pm and resulted in two of Kawerau's three timber mills being evacuated.

Staff from Asaleo Care and Carter Holt Harvey mills were instructed to leave the building after the jolt while no action was taken at the nearby Norske Skog plant.

This morning Asaleo Care workers were made to wait as a site assessment was carried out.

No one from either of the mills could be reached for comment.

Reports of a large bang and a continual hissing noise reported on social media by Kawerau residents could not be confirmed today.

Residents had suggested geothermal pipes were being vented as a precautionary measure or had burst due to the earthquakes.

The first of six earthquakes hit at 6.20pm yesterday - a 3.5-magnitude quake Geonet classified as "weak", which hit 25km south-west of Whakatāne.

Valarie Reive from Kawerau was one of more than 400 people who reported feeling it.

"It was really scary last night to the point we wanted to run outside ... we all got zero sleep," Reive said.

She said there had been dozens of warning posts on their community Facebook page.

"Some people are saying to get blankets and supplies and get out. They have just been so regular. We don't really know what to do," Reive said.

Another, slightly weaker quake hit half an hour later nearby, then two more 40 minutes after that within 5km of one another.

The strongest of the two which hit together about 7.20pm was 3.9 magnitude, 20km west of Whakatāne.

About the same time, Bay of Plenty Civil Defence announced on Facebook the area was experiencing a "swarm" of earthquakes, which could be felt in Whakatāne and Kawerau.

"We have been in touch with the GNS Duty Seismologist they are keeping an eye on things - they are happy that its just a typical swarm," the post read.

Things quietened down in the region until shortly after 11pm, when a 4.1-magnitude quake classed as "light" by Geonet and felt by 575 people struck 2km deep 25km west of Whakatāne.

It was followed an hour later just after midnight by a 3.6-magnitude quake 6km deep and 25km south west of Whakatāne.

All in all, nearly 2000 people logged reports with Geonet saying they'd felt the six quakes.