Possible Dual Earthquake–Landslide Source of the 13 November 2016 Kaikoura, New Zealand Tsunami

Mohammad Heidarzadeh, Kenji Satake

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23 Citations (SciVal)

Abstract

A complicated earthquake (Mw 7.8) in terms of rupture mechanism occurred in the NE coast of South Island, New Zealand, on 13 November 2016 (UTC) in a complex tectonic setting comprising a transition strike-slip zone between two subduction zones. The earthquake generated a moderate tsunami with zero-to-crest amplitude of 257 cm at the near-field tide gauge station of Kaikoura. Spectral analysis of the tsunami observations showed dual peaks at 3.6–5.7 and 5.7–56 min, which we attribute to the potential landslide and earthquake sources of the tsunami, respectively. Tsunami simulations showed that a source model with slip on an offshore plate-interface fault reproduces the near-field tsunami observation in terms of amplitude, but fails in terms of tsunami period. On the other hand, a source model without offshore slip fails to reproduce the first peak, but the later phases are reproduced well in terms of both amplitude and period. It can be inferred that an offshore source is necessary to be involved, but it needs to be smaller in size than the plate interface slip, which most likely points to a confined submarine landslide source, consistent with the dual-peak tsunami spectrum. We estimated the dimension of the potential submarine landslide at 8–10 km.

Original languageEnglish
Pages (from-to)3737-3749
Number of pages13
JournalPure and Applied Geophysics
Volume174
Issue number10
DOIs
Publication statusPublished - 1 Oct 2017

Bibliographical note

Funding Information:
Tide gauge records are from the network operated by GNS Science and Land Information New Zealand, accessed from Intergovernmental Oceanographic Commission’s Sea Level Station Monitoring Facility (http://www.ioc-sealevelmonitoring.org/). The earthquake source model of USGS was used in this study (https://earthquake.usgs.gov/earthquakes/eventpage/ us1000778i#executive). We thank Ian Hamling (GNS Science, New Zealand) for sharing his source model with us. Early results were presented at the annual tsunami symposium of the Japan tsunami community on 8, 9 December 2016 at the Kansai University, Osaka, Japan. We are grateful for the constructive comments from colleagues participating in this symposium. The manuscript benefited from constructive review comments by Alexander Rabinovich (Editor-in-Chief), Emily M Lane (NIWA, New Zealand), and an anonymous reviewer. We thank Yefei Bai for providing the Sumner tide gauge record. This research was funded by Brunel Research Initiative and Enterprise Fund 2017/18 (BUL BRIEF) at the Brunel University London to the lead author (MH).

Publisher Copyright:
© 2017, The Author(s).

Keywords

  • 2016 Kaikoura earthquake
  • landslide
  • New Zealand
  • numerical simulations
  • spectral analysis
  • submarine mass failures
  • tsunami

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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