High quality GPS and differential InSAR data have been collected for determining the ground deformation associated with the September 2010 Darfield (Canterbury) earthquake. We report preliminary results from a subset of these data and derive a preliminary source model for the earthquake. While the majority of moment release in the earthquake occurred on the strike-slip Greendale Fault a number of other fault segments were active during the earthquake including a steeply southeast-dipping thrust fault coincident with the earthquake hypocentre.