Highly variable coastal deformation in the 2016 MW7.8 Kaikōura earthquake reflects rupture complexity along a transpressional plate boundary
Date
2017
Authors
Clark, K.J.
Nissen, E.K.
Howarth, J.D.
Hamling, I.J.
Mountjoy, J.J.
Ries, W.F.
Jones, K.
Goldstien, S.
Cochran, U.A.
Villamor, P.
Journal Title
Journal ISSN
Volume Title
Publisher
Earth and Planetary Science Letters
Abstract
Coseismic coastal deformation is often used to understand slip on offshore faults in large earthquakes but in the 2016 MW7.8 Kaikōura earthquake multiple faults ruptured across and sub-parallel to the coastline. Along ∼110 km of coastline, a rich dataset of coastal deformation comprising airborne lidar differencing, field surveying and satellite geodesy reveals highly variable vertical displacements, ranging from −2.5 to 6.5 m. These inform a refined slip model for the Kaikōura earthquake which incorporates changes to the slip on offshore faults and inclusion of an offshore reverse crustal fault that accounts for broad, low-amplitude uplift centered on Kaikōura Peninsula. The exceptional detail afforded by differential lidar and the high variability in coastal deformation combine to form the highest-resolution and most complex record of coseismic coastal deformation yet documented. This should prompt reassessment of coastal paleoseismic records that may not have considered multi-fault ruptures and high complexity deformation fields.
Description
Keywords
coastal deformation, multi-fault rupture, Kaikōura earthquake, lidar differencing, plate boundary
Citation
Clark, K.J., Nissen, E.K., Howarth, J.D., Hamling, I.J., Mountjoy, J.J., Ries, W.F., … Strong, D.T. (2017). Highly variable coastal deformation in the 2016 MW7.8 Kaikōura earthquake reflects rupture complexity along a transpressional plate boundary. Earth and Planetary Science Letters, 474(September), 334-344. http://dx.doi.org/10.1016/j.epsl.2017.06.048