ABSTRACT

The upper North Island of New Zealand has large concentrations of population and infrastructure that make it vulnerable to earthquakes on the Kerepehi and Wairoa North faults. Using a physics-based simulator, we modelled 0–50 Hz ground motions for M_w 7.3 and M_w 6.6 characteristic earthquakes on these structures. We considered the effects of low-velocity basins beneath the Hauraki Rift and the city of Hamilton that can amplify ground shaking. For a Kerepehi Fault earthquake, long period (>1s) shaking was amplified a by factor of two to three in Hamilton and towns near the Firth of Thames. Severe to violent, long duration shaking would occur close to the source with the potential to trigger liquefaction that damages flood defence networks and farmland in the Hauraki Depression. Auckland, Hamilton and Tauranga could experience moderate to very strong shaking. Impacts in Auckland are larger for a Wairoa North Fault earthquake, which could generate peak ground accelerations of 0.5g at reservoir dams in the Hūnua Ranges, 0.2g at the international airport, and 0.1–0.2g at the CBD and port. Road, rail and transmission networks are vulnerable to disruption where they converge at infrastructure hotspots 10 km from the fault in South Auckland.

摘要

新西兰上北岛人口和基础设施高度集中，因此在 Kerepehi 和 Wairoa North 断层上容易发生地震。使用基于物理的模拟器，我们为 M _w 7.3 和 M _w模拟了 0–50 Hz 地面运动6.6 这些结构上的特征地震。我们考虑了豪拉基裂谷和汉密尔顿市下方的低速盆地会放大地面震动的影响。对于 Kerepehi 断层地震，在汉密尔顿和泰晤士湾附近的城镇中，长时间（> 1 秒）的震动被放大了 2 到 3 倍。源头附近会发生严重到剧烈、持续时间长的震动，并有可能引发液化，从而破坏 Hauraki 洼地的防洪网络和农田。奥克兰、汉密尔顿和陶朗加可能会经历中度到非常强烈的震动。Wairoa North Fault 地震对奥克兰的影响更大，这可能在 Hūnua Ranges 的水库大坝产生 0.5g 的峰值地面加速度，在国际机场产生 0.2g，在 CBD 和港口产生 0.1-0.2g。路，