A swarm of earthquakes has been triggered off the North Island's east coast by a large seismic event similar to what preceded the 2011 Japanese quake and tsunami. GNS Science has confirmed one of the largest "slow-slips" ever observed in New Zealand is currently underway off the coast of Gisborne in the Hikurangi subduction zone.

This slow-slip began last week and so far scientists have recorded "up to 3cm of eastward displacement," said Wallace.

"This is caused by up to 10-15cm of movement on the Hikurangi plate boundary offshore of Gisborne."

While these events are fairly common, happening every one or two years, this slow-slip is on track to be "as large at the previous slow-slip" recorded off Gisborne in 2010.

Since Monday, 85 quakes have been recorded in the area.

https://www.sott.net/article/410709-Earthquake-swarm-and-huge-slow-slip-event-at-New-Zealands-North-Island