Geometry of the wellington fault (New Zealand) defined by 3-D georadar data

Earthquakes with 7.3-7.9 magnitudes strike the Wellington Fault at intervals of 500-770 years. Because the last event likey happened 344-494 years ago, the Wellington Fault, which passes through Wellington and the densely populated Hutt Valley, is considered to be a highly hazardous structure. On 3-D georadar data collected across the Wellington Fault within the Hutl Valley, the first ever fault-plane reflections from an active strike-slip fault are observed. They are associated with conspicuous diffractions generated by abrupt truncations of structures against the fault plane. These georadar data provide the imost vivid shallow images of any active fault surveyed to date.. Prominent reflection fabrics that parallel the trends of the Wellington FauIt are observed everywhere across the 25 x 50 m survey site, providing a minimum estimate of the lateral extent of shearing, fracturing, and crushing associated with faulting.