Reason for swarm of Bay of Plenty earthquakes found

Scientists appear to have found the cause of a recent swarm of thousands of earthquakes in the eastern Bay of Plenty.

A new study from GNS Science investigated why the coastal town of Matata recorded twice as many earthquakes as normal between 2004 and 2011.

Using modelling, scientists found a previously unrecognised magma chamber was accumulating nine kilometres underground.

Leader author Dr Ian Hamling said the quakes and surface swelling of the land were caused by magma intruding into the Earth's crust.

"It causes a rock above to uplift and to form that deformation that causes the rocks to crack and that's when we see these earthquake swarms."

Dr Hamling said the finding didn't mean there was a high risk of a volcanic eruption but it did show New Zealand was geologically active.

He said for them to observe a build-up of magma in an area where scientists wouldn't traditionally look for magma was quite surprising and quite unique.

Dr Hamling said very little was known about how tectonic plates related to build-ups of magma underground.

http://www.newstalkzb.co.nz/news/upper-north-island/reason-for-swarm-of-bay-of-plenty-earthquakes-found/