What natural disaster struck Christchurch in 2011?

The natural disaster that struck Christchurch in 2011 was an earthquake. This devastating earthquake occurred on February 22, measuring 6.3 on the Richter scale, and it caused significant destruction throughout the city, leading to loss of lives, injuries, and widespread damage to infrastructure. The event was part of a series of seismic activities in the Canterbury region, but the 2011 earthquake was particularly catastrophic because of its shallow depth and proximity to the city center. This earthquake highlighted New Zealand's vulnerability to seismic activity, being situated on the Pacific Ring of Fire, where tectonic plate movements are common.

While volcanic eruptions, tsunamis, and flooding are all natural disasters that can occur in New Zealand, it was the earthquake that specifically caused the profound impact on Christchurch in 2011, making it the correct answer.