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Geographic Area Covered 

Kapiti Coast District, located in the Wellington region of New Zealand, including areas from Transmission Gully to Otaki Forks and surrounding hill country. 

Summary of the Report 

This report presents the findings of a fault trace survey conducted by GNS Science for the Kapiti Coast District Council. The survey identifies five active faults traversing the district: Ohariu, Northern Ohariu, Gibbs, Otaki Forks, and Southeast Reikorangi faults. The study aims to support land use planning by defining fault locations, recurrence intervals, and fault avoidance zones, using guidelines from the Ministry for the Environment (MfE). The methodology includes air photo interpretation, field mapping, and integration of previous geological studies. Fault features were classified by their visibility and accuracy of location, and fault complexity was assessed to determine the likelihood and extent of surface rupture. Each fault was assigned a recurrence interval class based on estimated frequency of rupture events, ranging from Class II (more active) to Class IV (less active). Fault avoidance zones were mapped with widths varying from 40 to over 300 meters depending on fault complexity and certainty of location. The report outlines how building importance and site development status influence the level of risk and appropriate resource consent categories. For example, temporary structures may be permitted in higher-risk zones, while critical facilities are restricted from fault-prone areas. Recommendations include improving fault location accuracy through further geological investigations, refining recurrence interval estimates, and ensuring consistent planning policies across regional boundaries. The report provides a framework for integrating fault hazard information into district planning to mitigate risks associated with earthquake-induced surface rupture.