Nearly six months later on Tuesday 22 February 2011, a second earthquake measuring magnitude 6.3 struck the city at 12:51 pm. It was located closer to the city, near Lyttelton at a depth of 5 km. Although lower on the moment magnitude scale than the previous earthquake, the intensity and violence of the ground shaking was measured to be MM IX, among the strongest ever recorded globally in an urban area and in total 185 people were killed with nationals from more than 20 countries among the victims. Widespread damage was caused across Christchurch to buildings and infrastructure already weakened by the 4 September 2010 earthquake and its aftershocks. Significant liquefaction affected the eastern suburbs and parts of the central city, and the total cost to insurers of rebuilding has been estimated at NZ$20–30 billion. Due to an older building stock, and many buildings being multi-storey, the central city was hit especially hard.