Re-evaluation of New Zealand seismic hazard for geotechnical assessment and design

- Ross Roberts

An important new paper from Misko Cubrinovski, Brendon Bradley, Rick Wentz and Ananth Balachandra has been published in Vol 54 No 2 (2021) of the Bulletin of the New Zealand Society for Earthquake Engineering.

We recommend that all geotechnical engineers operating in New Zealand read this paper. The key finding is that NZS1170.5, and NZTA Bridge Manual in particular, significantly underestimate the PGA hazard for locations that are at a short source-to-site distance from the Hikurangi Subduction Zone and for which the Zone significantly contributes to their hazard. New PGA hazard is recommended for geotechnical earthquake practice.

The NZGS strongly recommends the use of the information in this paper during geotechnical design, particularly for those operating in the are from Gisborne to Blenheim (including Wellington and Whanganui).

The paper is available here, or the full Bulletin here.

Ross Roberts
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