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Effects Phase

The underlying goal of the Effects Phase is better definition of earthquake ground shaking and liquefaction hazard in Wellington City, the Hutt Valley, and the wider region. The ground shaking results will provide input to the Impacts Phase of It’s Our Fault, during which the earthquake damage, recovery time and social ramifications will be evaluated.

Work undertaken so far as part of the Effects Phase is focusing on:

  • Geological and Geotechnical Characterisation, to improve ground shaking amplification maps, estimate earthquake site effects, derive measures of liquefaction hazard, and facilitate detailed modelling and comparison of earthquake ground motion responses.
  • Subduction Interface Earthquake Motions, to simulate earthquake ground motion that could be produced by plausible subduction interface rupture scenarios, and provide input for modelling the effects of this class of major earthquake.
  • Liquefaction, to probabilistically model the occurrence and severity of liquefaction across the Wellington region.
  • Ground Motion Modelling, to compare and understand the amplification effects of the various subsoil conditions in Wellington and Lower Hutt to weak through to very strong earthquake shaking.

There are a number of publications (including journal articles, conference abstracts, progress reports and task completion reports) that document the research undertaken within the Effects Phase of It’s Our Fault. Click here to access the publications listed below.


Geological, Geotechnical, and NZS 1170 Subsoil Characterisation

Wellington City CBD

  • Perrin & others. 2010. Site class determinations (NZS 1170.5) in Wellington using borehole data and microtremor techniques. (Conference abstract).
  • Semmens & others. 2010. It’s Our Fault – Geological and Geotechnical Characterisation of the Wellington Central Business District. (Task completion report).
  • Semmens & others. 2010. What lies beneath: Geological and geotechnical characterisation of the Wellington central commercial area. (Conference abstract).
  • Semmens & others. 2011. NZS 1170.5:2004 site subsoil classification of Wellington City. (Conference abstract).

Lower Hutt

  • Boon & others. 2010. It’s Our Fault – Geological and Geotechnical Characterisation and Site Class Revision of the Lower Hutt Valley. (Technical summary).
  • Boon & others. 2011. NZS1170.5:2004 Site Subsoil Classification of Lower Hutt. (Conference abstract).

Ground motion site effects terms as a continuous function of site period and Vs30

  • McVerry 2011. Site-effect terms as continuous functions of site period and Vs30. (Conference abstract).

Seismic Instrumentation and Inversion for Physical Parameters of Wellington and the Hutt Valley

  • Fry & others. 2010. It’s Our Fault – Seismic instrumentation and inversion for physical parameters of Wellington and the Hutt Valley. (Task completion report).

Subduction Zone Ground Motion Simulations

  • Holden & Zhao. 2011. Modelling Strong Ground Motions for Subduction Events in the Wellington Region, New Zealand. (Conference abstract).
  • Holden & others. 2013. Ground motion modelling of a large subduction interface earthquake in Wellington, New Zealand. (Conference abstract).
  • McVerry & Holden. 2014. Incorporating simulated Hikurangi subduction interface spectra into probabilistic hazard calculations for Wellington. (Conference abstract).
  • McVerry & Holden. 2014. A modified ground-motion prediction equation to accommodate spectra of simulated Hikurangi subduction interface motions for Wellington. (Task completion report).

Earthquake ground motion modelling of local site effects

  • Kaiser & others. 2012. It’s Our Fault: Ground motion modelling of local site effects in the Wellington region. (Task completion report).