Well, the article does say nobody was hurt (there's something magic in the water in New Zealand), but still, that's a pretty big quake, and it hit my father's hometown, and my grandparents still live there.
No, wait, this article says one dead, twenty injured. Nothing about any of my relatives, though, so far as I can see.
Here's the official Geonet report.
This one's entitled "Latest updates", so maybe I'll keep that one open and refresh it periodically.
Anyway, from what I've seen online so far, I probably don't need to worry about my grandparents. I imagine they have quite a mess to clean up, though.