2011 Christchurch Earthquake (M6.3) — New Zealand's Deadliest Disaster

At 12:51 p.m. on 22 February 2011, a magnitude 6.3 earthquake struck almost directly beneath Christchurch, New Zealand's second-largest city, at a shallow depth of only about 5 km. It was an aftershock of the larger magnitude 7.1 Darfield earthquake that had jolted the wider Canterbury region five months earlier, but it ruptured a previously unmapped fault far closer to the city centre, producing some of the most violent ground accelerations ever recorded near a major urban area.

Despite its smaller magnitude, the quake killed 185 people, New Zealand's deadliest disaster since the 1931 Hawke's Bay earthquake. Most deaths came from two building collapses: the six-storey Canterbury Television (CTV) building, which killed 115 people, and the Pyne Gould Corporation (PGC) building, which killed 18 more. Falling masonry and rockfall from the Port Hills claimed further lives across the city.

Widespread liquefaction turned soft, water-saturated ground in the eastern suburbs into a shifting slurry, burying streets and homes in silt and leaving thousands of properties too damaged to repair. The historic ChristChurch Cathedral in Cathedral Square lost its spire and suffered severe structural damage, becoming the visual symbol of a central business district that stayed cordoned off for years. Total losses reached roughly NZ$40 billion, New Zealand's costliest natural disaster on record.

The disaster forced a fundamental rethink of urban seismic risk in New Zealand. A residential red zone permanently retired thousands of the worst-hit eastern-suburb properties, building codes were tightened nationwide, and a years-long central-city rebuild replaced much of the historic CBD. GNS Science continues to closely monitor the Canterbury fault network, which remains active more than a decade on.