Hikurangi Subduction modelling
Natural Hazard Research Platform funded project
Research Overview
Large mega-thrust earthquakes, such as the 2011 Tohoku-oki earthquake in Japan, occur at subduction zones. In the lower North Island of New Zealand, the absence of recorded past large mega-thrust earthquakes and a unique tectonic situation preclude the use of purely empirical approaches to estimate the resulting ground-motion levels. Understanding earthquake source parameters controlling the levels of ground motions from destructive mega-thrust earthquakes is critical for seismic hazard assessments.
We derive key parameters for the engineering specification of seismic ground motions for the lower North Island of New Zealand using advanced wavefield simulations of plausible mega-thrust earthquakes through:
- developing an extensive set of potential rupture scenarios for magnitude 8+ earthquakes
- computing ground motions using a hybrid method that incorporates both deterministic and stochastic approaches at low and high frequencies, respectively.
- capturing a greater variability of strong ground motions across the lower North Island at both high and low frequencies.
Research work as part of It’s Our Fault project:
It’s Our Fault funded project
The goal of the It’s Our Fault programme is to see Wellington positioned to become a more resilient city through a comprehensive study of the likelihood of large Wellington earthquakes, the effects of these earthquakes, and their impacts on humans and the built environment.
The It’s Our Fault programme comprises three main phases: Likelihood, Effects and Impacts.
Ground motion modelling of Hikurangi earthquake source seats under the effect phase.
Research outcomes from the project are:
- Ground motion modelling of a large subduction interface earthquake in Wellington, New Zealand (Holden and Zhao, 2011, 2013)
- A modified ground-motion prediction equation to accommodate simulated Hikurangi subduction interface motions for Wellington (McVerry and Holden, 2014)
- Ground motion modelling of local site effects in the Wellington region (Kaiser et al., 2012; 2014)
1947 Tsunami earthquakes
Hikurangi margin tsunami earthquake generated by slow seismic rupture over a subducted seamount (Bell et al., 2014)