Road impacts from the 2016 Kaikōura earthquake: an analogue for a future Alpine Fault earthquake?

Robinson, T.

Abstract

The 2016 MW 7.8 Kaikōura earthquake involved complex rupture of multiple faults for > 170 km, generating strong ground shaking throughout the upper South Island leading to widespread landsliding. As a result of surface fault rupture and landslides, State Highway (SH) 1 and SH70 were blocked, isolating Kaikōura and the surrounding communities, and necessitating evacuations by air and sea. In all these respects, the Kaikōura earthquake can be considered an analogue for a future Alpine Fault earthquake, providing lessons for the necessary emergency response. Landslide blockages primarily occurred where surrounding slopes averaged > 17° and where peak ground acceleration was > 0.43 g, peak ground velocity was > 41 cm/s, or the modified Mercalli intensity was > 7.9. Using a potential future Alpine Fault scenario earthquake, this study identifies locations on other key state highway routes that have similar predictive variables that may, therefore, become blocked in a future earthquake. This suggests that SH6 between Hokitika and Haast, SH73 near Arthur’s Pass, and SH94 south of Milford Sound are all likely to be affected. This will necessitate the evacuation of large numbers of spatially distributed tourists as well as the resupply of isolated local populations. The possibility of bad weather along with a lack of sea ports south of Hokitika will likely make such activities challenging. Contingency planning based on experiences from the Kaikōura earthquake is therefore necessary and likely to prove invaluable following an Alpine Fault earthquake.

Citation

Robinson, T. (2018). Road impacts from the 2016 Kaikōura earthquake: an analogue for a future Alpine Fault earthquake?. New Zealand Journal of Geology and Geophysics, 61(3), 403-411. https://doi.org/10.1080/00288306.2018.1470539

• Journal Article Type: Article
• Acceptance Date: Apr 24, 2018
• Online Publication Date: May 21, 2018
• Publication Date: Jul 3, 2018
• Deposit Date: May 15, 2018
• Publicly Available Date: May 21, 2019
• Journal: New Zealand Journal of Geology and Geophysics
• Print ISSN: 0028-8306
• Electronic ISSN: 1175-8791
• Publisher: Taylor and Francis Group
• Peer Reviewed: Peer Reviewed
• Volume: 61
• Issue: 3
• Pages: 403-411
• DOI: https://doi.org/10.1080/00288306.2018.1470539
• Public URL: https://durham-repository.worktribe.com/output/1326513