Postseismic Deformation Following the 2016 Mw 7.8 Kaikōura Earthquake, New Zealand
Abstract
The M7.8 Kaikōura earthquake, took place in the northeastern South Island of New Zealand on 14 November 2016, NZ local time. It ruptured within a complex tectonic region, where the subduction along the Hikurangi margin to the north transitions to strike-slip and collision along the Alpine Fault in the south. The earthquake ruptured over 170 km with significant slip along at least 12 major crustal faults and possibly portions of the subduction plate interface beneath the region. We present results of GNSS and InSAR measurements of the post-earthquake deformation in the region. In the first few days/weeks following the earthquake GNSS sites around the fault ruptures were measured and new continuous and semi continuous GNSS stations installed. In early 2017 and early 2018 GNSS measurements of the entire Top of the South Island (TOPS) campaign GNSS network were undertaken, greatly enhancing the spatial coverage of post-seismic deformation in the years following the earthquake. Postseismic deformation in the first few months following the Kaikōura earthquake shows a large-scale northeast-directed movement along with an uplift/subsidence pair, with the most rapid deformation observed in the region of Cape Campbell (northeast tip of South Island), coinciding with a large cluster of aftershocks. Such a surface displacement field is not easily explained by afterslip on crustal faults that ruptured in the earthquake alone. The overall pattern and scale of post-earthquake deformation is more consistent with slip on a low-angle source at depth, such as the subduction interface beneath the northern South Island.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.G21A..01H
- Keywords:
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- 1207 Transient deformation;
- GEODESY AND GRAVITYDE: 1211 Non-tectonic deformation;
- GEODESY AND GRAVITYDE: 8159 Rheology: crust and lithosphere;
- TECTONOPHYSICSDE: 8163 Rheology and friction of fault zones;
- TECTONOPHYSICS