Bad day to go fishing out there I guess. :) Hopefully its going to actualize in non populated areas.
It’s probably silly for me to speculate, but I will anyway...
The West Coast of the South Island has a spine of solid rock called the Southern Alps, running from top-to-bottom. This lies along a fault line — hence the Alps and the many earthquakes that happen there.
If I had to guess I’d say this earthquake would have been on that fault line. And any resultant Tsunami has got alot of water to move before it hits shore: the water is quite deep there.
When it gets to shore, it has the fjords in Fjordland to use up its energy on — and that’s long before it even reaches Nelson.
My guess is that it isn’t going to amount to much.
(and with my luck I could be horribly wrong. Let’s hope not!)