Characterisation of transport resilience and measures to enhance resilience in the recovery after the 2016 Kaikōura earthquake

Abstract

The Ward to Cheviot section of State Highway 1 is a key lifeline transport route that runs through the Kaikōura township.  It is a strategically important link in the national state highway network, connecting the North Island via the Wellington-Picton ferry to the city of Christchurch in the South Island.  Its strategic importance and vulnerable location between the mountainous Kaikōura range and the Pacific Ocean make it a critical transportation route in the national transport network.  The route has been a focus for understanding the resilience of transport networks from as far back as 2000, when this section was used as a pilot study in early research into transport resilience.  A further resilience assessment of this section was completed as part of a national state highway resilience study in mid-2016.  Subsequently, the Mw 7.8 Kaikōura earthquake struck the northeast of the South Island on 14 November 2016, triggering thousands of large landslides and causing severe disruption to the transport network.  The damage and disruption caused by the earthquake was comparable to that assessed in pre-earthquake studies of the resilience of the state highway.  Landslides and embankment failures caused the most damage and disruption to the transport infrastructure, with the Main North Line railway closed for over 9 months and State Highway 1 closed for over a year.  Post-earthquake landslides and debris flows triggered by storms caused additional damage and disruption during the recovery phase. Post-earthquake assessment of the corridor resilience was carried out to identify measures to enhance resilience as part of the recovery works.  These measures included realigning the road and rail away from the steep hillsides, engineered works to reduce the potential for slope failure, and engineered works to reduce the potential for inundation of the corridor.  The resilience assessments also enabled tactical and operational measures to be put in place to ensure safety while allowing the recovery operations to proceed in the context of enhanced risk associated with storm events and potential aftershocks.