If you look around Canterbury, there are numerous faults mapped in the foothills. There are also numerous faults mapped offshore that have no mapped onshore equivalent. The sustainability of future social and economic development in Canterbury hinges on a robust understanding of our seismic hazard. As I say elsewhere, the identification and characterization of presently-hidden fault sources and their linkages is very important in light of the recent Canterbury Earthquake Sequence, in which multiple fault segments ruptured in close succession. Therefore, the lack of understanding of active fault sources immediately north of the Waimakariri River is concerning.