On 4 September 2010, a surface rupturing earthquake (Mw 7.1) struck the Canterbury Plains region in New Zealand's South Island. The Canterbury Plains is a region of relatively low seismicity, and the structure that ruptured was a previously unmapped fault. The earthquake has been followed by more than 10,000 catalogued aftershocks, including two of magnitude 6.0 and one of magnitude 6.2. On 22 February 2011 a destructive Mw 6.2 aftershock with shallow depth struck approximately 8 km southeast of downtown Christchurch, causing extensive damage in the central city and its eastern suburbs and 185 fatalities. This earthquake was very energetic, with recorded maximum vertical accelerations of 2.2 g near the epicentre. On 13 June 2011 a further aftershock of magnitude (Mw) 6.0 struck Christchurch. It was located only a few km east of the previous event, and again caused extensive damage, landslides, rock falls and liquefaction. Accelerations over 2g were also recorded. On 23 December 2011 Christchurch was again struck by two large aftershocks, 2 hours apart, of magnitude (Ml) 5.8 and 6.0. These were located offshore, about 10 km east of the central city. Unlike the Mw 7.1 event no surface rupture has been found for any of the large aftershocks. The source process of all of these events have been well constrained by geodetic and seismological data. We present a preliminary earthquake sequence based on kinematic 

source models of the earthquakes.