The 2010 Canterbury earthquake (also known as the Darfield earthquake) struck the South Island of New Zealand with a moment magnitude of 7.1 at 4:35 am local time on 4 September, and had a maximum perceived intensity of X (Extreme) on the Mercalli intensity scale. Some damaging aftershocks followed the main event, the strongest of which was a magnitude 6.3 shock known as the Christchurch earthquake that occurred nearly six months later on 22 February 2011. Because this aftershock was centred very close to Christchurch, it was much more destructive and resulted in the deaths of 185 people.