Here's what the United States Geological Survey has to say:

Two people seriously injured. Six bridges and many buildings damaged at Christchurch. More than 5 km of right-lateral surface faulting was observed southeast of Darfield.

Tectonic Summary
The September 3, 2010 South Island, New Zealand earthquake occurred as a result of strike-slip faulting within the crust of the Pacific plate, near the eastern foothills of the Southern Alps at the western edge of the Canterbury Plains.

The earthquake struck approximately 50 km to the west-northwest of Christchurch, the largest population center in the region, and about 80-90 km to the south and east of the current expression of the Australia:Pacific plate boundary through the island (the Alpine and Hope Faults). The earthquake, though removed from the plate boundary itself, likely reflects right-lateral motion on one of a number of regional faults...

Translation: the Pacific plate and the Australian plate are rubbing horizontally against one another. 5 km of fresh new fault (split ground) has appeared near Darfield. Whichever side of the fault you stand on, the other side will appear to have moved to the right.

I think you can quit worrying about the volcanoes. If they haven't started to quiver or smoke yet, they are probably unaffected by the motion of the plates. I'm sure if there was any bad news, the press would let us all know.

Meanwhile:

is your water heater strapped to a wall?

do you have shoes right near your bed to put on if a quake strikes in the night? (to protect from broken glass)

do you have a sturdy table or desk to hide under?

have you removed heavy pictures or mirrors that could fall on you?

Little things can make a big difference.