Reconciling the deformational dichotomy of the 2016 Mw 7.8 Kaikoura New Zealand earthquake

Abstract

Following the 2016 Mw 7.8 Kaikoura earthquake, uncertainty over the nature of the coseismic rupture developed. Seismological evidence pointed to significant involvement of the subduction megathrust, while geodetic and field observations pointed to a shallow set of intracrustal faults as the main participants during the earthquake. The addition of tsunami observations and modeling as reported in Bai et al. (2017) places additional constraints on the specific location of coseismic slip, which when combined with other observations indicates the simultaneous occurrence of shallow slip on the subduction interface and slip on overlying, upper crustal fault structures. This Kaikoura-style earthquake, involving synchronous ruptures on multiple components of the plate boundary, is an important mode of plate boundary deformation affecting seismic hazard along subduction zones.