The Marlborough Fault System is a bundle of major right-lateral strike-slip faults across the northeastern South Island of New Zealand, including the Wairau, Awatere, Clarence and Hope faults. It transfers slip from the Alpine Fault to the Hikurangi Subduction Zone, splaying the plate motion across several parallel strands.
Together these faults accommodate most of the horizontal motion between the Pacific and Australian plates in this region, sliding at rates of up to around 2 centimetres per year on the fastest strands. The system carves a striking series of long, straight, parallel valleys across the Marlborough landscape, each following an individual fault.
The 2016 Kaikoura earthquake (magnitude ~7.8) dramatically ruptured a cascade of faults within and adjacent to this system, producing spectacular surface breaks and coastal uplift. The event demonstrated how multiple Marlborough faults can rupture together in a single complex earthquake, complicating hazard assessment for the region.