Earthquake source parameters of the 2009 M_W7.8 Fiordland (New Zealand) earthquake from L-band InSAR observations

The 2009 M_W7.8 Fiordland (New Zealand) earthquake is the largest to have occurred in New Zealand since the 1931 M_W7.8 Hawkeos Bay earthquake, 1 000 km to the northwest. In this paper two tracks of ALOS PALSAR interferograms (one ascending and one descending) are used to determine fault geometry and slip distribution of this large earthquake. Modeling the event as dislocation in an elastic half-space suggests that the earthquake resulted from slip on a SSW-NNE orientated thrust fault that is associated with the subduction between the Pacific and Australian Plates, with oblique displacement of up to 6.3 m. This finding is consistent with the preliminary studies undertaken by the USGS using seismic data.