
Litchfield, N.J.; Clark, K.J.; Ries, W.F.; Villamor, P.; Van Dissen, R.J.; Langridge, R.M.; Jones, K.E.; Heron, D.W.; Lukovic, B.; Townsend, D.B.; Barrell, D.J.A.; Pettinga, J.; Nicol, A.; Fenton, C.; Khajavi, N.; Little, T.; Kearse, J.; Rowland, J.; Canva, A.; Stirling, M.W.; Williams, J. 2018 Kaikōura Earthquake Short-Term Project: inventories of onshore surface fault ruptures and coastal uplift. Final report. GNS Science miscellaneous series 111. 16 p.; doi: 10.21420/G2B93F
Abstract: Ground deformation in the 14th November 2016 magnitude 7.8 Kaikōura Earthquake was extra-ordinarily complex, including multiple (>20) ground-surface fault ruptures and extensive (>110 km) coastal uplift. This report documents work undertaken after the initial GeoNet response phase to document the ground-surface fault ruptures and coastal uplift, with a large focus on high resolution topographic (Light Detecting and Ranging) data. This work provides essential information for better understand what happened in the earthquake, and to inform future seismic hazard and land use planning. Key findings for the coastal deformation are that it was highly variable along the coast, ranging from uplift of 6.5 m to subsidence (land drop) of 2.5 m. The coastal deformation is almost all the result of movement on crustal faults, including one beneath Kaikōura Peninsula. Ground-surface fault ruptures have now been documented on 24 faults, about half of which were not recognised as active faults before the earthquake. About a third were included in the 2010 version of the New Zealand National Seismic Hazard Model, including a multi-fault source. Maximum ground-surface fault displacement was ~12 m on the Kekerengu Fault, but slip distributions show that the displacement varied along the faults, as documented on other ground-surface fault ruptures from around the globe. Future work includes paleoseismological studies to obtain information on the timing and magnitude of past earthquakes. This information will be used to better characterise multi-fault ruptures and incorporation of time dependent seismic hazard in seismic hazard models. (auth)