Large-Scale Earthquake-Induced Landslide Repair Following New Zealand's Kaikoura Earthquakes-Paper

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The magnitude 7.8 Kaikoura earthquake of November 2016 triggered dozens of major landslides, severing State Highway 1 and the Main North Rail Line and isolating Kaikoura. New Zealand established the North Canterbury Transport Infrastructure Recovery (NCTIR) alliance to restore the transport corridor, targeting road reopening by December 2017.<br /><br />The steep, unstable slopes and risk of aftershocks made conventional machinery unsafe or impractical. Initial work relied on helicopter-based water sluicing to dislodge loose material, followed by rope-access scaling, blasting, airbags, and remote-controlled excavators. These measures enabled limited road access and allowed longer-term stabilization to proceed.<br /><br />Permanent treatments included rock bolts or dowels combined with steel mesh, as well as rockfall barriers and debris-flow bunds. At Ohau Point, schedule pressure and difficult conditions prompted an accelerated, staged solution: a helicopter-installed ring-net drape was added first to contain falling debris and permit work below, followed later by the permanent pinned-mesh system. Other sites used specialized attenuators that captured rockfall while allowing debris to move to accessible collection areas.<br /><br />The project required extensive logistical coordination. Many sites were reachable only by helicopter, and fog, wind, winter weather, road closures, and limited emergency services regularly disrupted work. Materials, including ring net and shackles, had to be sourced internationally and flown into New Zealand.<br /><br />Despite these challenges, State Highway 1 reopened on 15 December 2017, while rail services were restored in September. Further safety works continued into 2018. The recovery demonstrated how rapid, sometimes unconventional measures, followed by engineered permanent solutions, could restore critical infrastructure after a major earthquake.

Keywords

Kaikoura earthquake

landslide recovery

State Highway 1

Main North Rail Line

NCTIR alliance

helicopter water sluicing

rockfall stabilization

ring-net drape

remote-controlled excavators

critical infrastructure restoration