When my wife and I were in NZ in 2013 I found this site interesting. Note the severe 6.3 mag Earthquake just 2 hours ago (search by severity) in same area as last nights. No doubt will go on for some time.
http://www.geonet.org.nz/quakes/felt
The drive through that mountainous area along the coast was spectacular, lots of fur seals, a lot of rebuilding on that highway and railway ahead. Hope there is nobody buried under there.