Abstract

The 2016 Kaikōura earthquake is one of the most complex earthquakes recorded by modern observation techniques. A comprehensive understanding of this event has not yet been achieved despite analysis of observed data. To advance clarification of the mechanism of the earthquake, we revealed detailed surface displacement caused by the earthquake using Advanced Land Observing Satellite 2 Synthetic Aperture Radar data and constructed fault models comprising rectangular planes with a uniform slip. Remarkably large and intricate surface displacements were detected in two distinct areas: (1) a southwestern part around the Hundalee fault and The Humps fault zone and (2) a northeastern part around the Kekerengu fault and the little recognized Papatea fault. A gap where the displacement is relatively small exists between the two major zones of faulting. In the southwestern part, extremely complicated displacements are disclosed in detail and have been modeled as an intricate set of six faults that include previously unknown structures. In the northeastern part, the largest displacement of 9  m was detected along the Kekerengu and Papatea faults. The modeled fault plane along the Kekerengu fault shows a large reverse and dextral slip and possibly released the largest seismic moment of all modeled fault segments. The constructed fault model also explains far‐field displacement, indicating that the dominant slip direction was right lateral, consistent with the strain field in this region. The calculated change of Coulomb failure stress (ΔCFS) suggests that the static stress changes by the southwestern fault segments may have contributed to triggering the northeastern fault segments.

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