1) "Kaikoura, sixty miles north of Christchurch" - it's closer to 90 miles - in a straight line across the ocean. If you are driving, it's even further.
2) "The North Island, where the capital, Wellington, lies, is part of the Australian plate, and its landscape is dominated by two dozen active volcanoes." - 24 active volcanoes in the North Island? Pity that we're only monitoring 11 of them then. https://www.geonet.org.nz/volcano/
3) "that the earthquake, like the one that devastated Christchurch in 2010" - It happened in 2011. The initiating earthquake happened in 2010, yes, but the aftershock that killed people and brought down buildings in ChCh occurred on Feb 22 2011.