Most buildings were damaged in the 2011 earthquake that was centred around Lyttelton, near Christchurch. Many of these buildings were beyond repair and were demolished (including the old part of London Street, which my other half had run as a restaurant only a year before the quake struck).
Unfortunately, the worst affected buildings were the old ones, with the most character. This included the cathedral. I've never been a huge fan of Christchurch Cathedral. I preferred some of the other religious buildings around the city (most of which were demolished). There was a lot of discussion about whether it should be saved and I was firmly in the camp of "let's move on". The earthquake was a chance for the city to reinvent itself as one that looked forward, not back. But there are a lot of people who don't want to let that English heritage go, so it looks like it is going to be rebuilt, at huge cost.