Just to reassure you - I live in Wellington area and didn't notice the earthquake tonight! I usually always feel the slightest little tremor! I live about 20k North of Wellington City. And being a life time resident of Wellington I'm extra sensitive and petrified of them too!
Just took this info from the Geonet site -
www.geonet.org.nz - interesting but not for would be immigrants to look at though

Reference Number: 3472164
NZDT: Tue, Mar 1 2011 10:07 pm
Magnitude: 4.5
Depth: 40 km
Details: 20 km north-west of Wellington
Tephra, as you probably know, Karori is a suburb of Wellington City, so your Aunt is even further away from the earthquake than I am and I'm sure she will be fine. .
If you are still online and would like to PM me with the name of the Rest Home, her name, and your name, I will be more happy to call them right now for you. Night staff will be on duty, and I'm sure it will be OK to ring now and I'd like to be able to put your mind at rest - straight from the horse's mouth!
Jeanne

Modified at 1.10am to add - "see you've gone offline now, but still PM me and I'll check it out in the morning for you."