An elderly nursing home resident in New Zealand was killed Monday when a series of aftershocks struck the earthquake-damaged city of Christchurch.

The aftershocks struck four months after a massive 6.3 magnitude quake that killed 181 people and either destroyed or damaged dozens of buildings in the city center. The strongest of Monday's aftershocks had a magnitude of 6.0.

At least 50 buildings that had already suffered extensive damage in the February 22 quake sustained further damage from Monday's aftershocks. A house in one seaside village tumbled off a cliff, while tens of thousands of homes were left without power during a freezing night. The power company Orion says power has now been restored to much of the city.