The volcanoes are in the north island, whereas Christchurch is in the south island, but New Zealand is not called the shaky isles for nothing, and the shocks were felt from Invercargill in the south, to Nelson in the north. The 7.1 magnitude is the same as the quake that hit Haiti in January, killing 230,000 people.
That said, however, this is the worst quake to hit NZ since the 1931 Napier earthquake, and it's a miracle no one was killed, although Christchurch hospital reported one death from heart attack, brought on by the quake.
My brother-in-law, who is a Kiwi and was camped alongside us for the last 3 nights (we are in Hervey Bay in our caravan) rang his father, who lives in Christchurch, yesterday. Fortunately the old (94) chap is OK, but a wall in his back yard collapsed on to the next door neighbour's house. A lot of damage has occurred in the Christchurch CBD, and power and water have been cut off to a large part of the affected areas.
Peter.