Ground motion and site effect observations in the wellington region from the 2016 Mw7.8 Kaikōura, New Zealand earthquake




This paper presents ground motion and site effect observations in the greater Wellington region from the 14 November 2016 Mw7.8 Kaikōura earthquake. The region was the principal urban area to be affected by the earthquake-induced ground motions from this event. Despite being approximately 60km from the northern extent of the causative earthquake rupture, the ground motions in Wellington exhibited long period (specifically T = 1 - 3s) ground motion amplitudes that were similar to, and in some locations exceeded, the current 500 year return period design ground motion levels. Several ground motion observations on rock provide significant constraint to understand the role of surficial site effects in the recorded ground motions. The largest long period ground motions were observed in the Thorndon and Te Aro basins in Wellington City, inferred as a result of 1D impedance contrasts and also basin-edge-generated waves. Observed site amplifications, based on response spectral ratios with reference rock sites, are seen to significantly exceed the site class factors in NZS1170.5:2004 for site class C, D, and E sites at approximately T=0.3-3.0s. The 5-95% Significant Duration, Ds595, of ground motions was on the order of 30 seconds, consistent with empirical models for this earthquake magnitude and source-to-site distance. Such durations are slightly longer than the corresponding Ds595 = 10s and 25s in central Christchurch during the 22 February 2011 Mw6.2 and 4 September 2010 Mw7.1 earthquakes, but significantly shorter than what might be expected for large subduction zone earthquakes that pose a hazard to the region. In summary, the observations highlight the need to better understand and quantify basin and near-surface site response effects through more comprehensive models, and better account for such effects through site amplification factors in design standards.


USGS (2016). “”.

GeoNet (2016). “”.

Kaiser A, Balfour N, Fry B, Holden C, Litchfield N, Ger-stenberger M, D’Anastasio E, Horspool N, McVerry G, Ris-tau J, Bannister S, Christophersen A, Clark K, Power W, Rhoades D, Massey C, Hamling I, Wallace L, Mountjoy J, Kaneko Y, Benites R, Van Houtte C, Dellow S, Wother-spoon L, Elwood K, and Gledhill K (2017). “The 2016 Kaikura, New Zealand, Earthquake: Preliminary Seismo-logical Report”. Seismological Research Letters, 88(3): 727– 739, DOI: 10.1785/0220170018. DOI:

Litchfield NJ, Benson A, Bischoff A, Hatem A, Barrier A, Nicol A, Wandres A, Lukovic B, Hall B, Gasston C, Asher C, Grimshaw C, Madugo C, Fenton C, Hale D, Barrell D, Heron D, Strong D, Townsend D, Nobe D, Howarth J, Pettinga J, Kearse J, Williams J, Manousakis J, Mountjoy J, Rowland J, Clark K, Pedley K, Sauer K, Berryman K, Hemphill-Haley M, Stirling M, Villeneuve M, Cockroft M, Khajavi N, Barnes P, Villamor P, Carne R, Langridge R, Zinke R, Van Dissen R, McColl S, Cox S, Lawson S, Little T, Stahl T, Cochran U, Toy V, Ries W, and Juniper Z (2016). “14th Novem-ber 2016 M7.8 Kaikoura Earthquake. Preliminary surface fault displacement measurements. Version 2. GNS Science. ”.

Hamling IJ, Hreinsdóttir S, Clark K, Elliott J, Liang C, Fielding E, Litchfield N, Villamor P, Wallace L, Wright TJ, D’Anastasio E, Bannister S, Burbidge D, Denys P, Gentle P, Howarth J, Mueller C, Palmer N, Pearson C, Power W, Barnes P, Barrell DJA, Van Dissen R, Langridge R, Little T, Nicol A, Pettinga J, Rowland J, and Stirling M (2017). “Complex multifault rupture during the 2016 Mw 7.8 Kaikura earthquake, New Zealand”. Science, DOI: 10.1126/science.aam7194. DOI:

Bradley BA, Razafindrakoto HNT, and Polak V (2017). “GroundMotion Observations from the 14 November 2016 Mw7.8 Kaikoura, New Zealand, Earthquake and Insights from Broadband Simulations”. Seismological Research Let-ters, 88(3): 740–756, DOI: 10.1785/0220160225. DOI:

Cubrinovski M, Bray J, de la Torre C, Olsen M, Bradley B, Chiaro G, Stocks E, and Wotherspoon L (2017). “Liq-uefaction effects and associated damages observed at the Wellington CentrePort from the 2016 Kaikoura earthquake”. Bulletin of the New Zealand Society for Earthquake Engi-neering, 50(2): 152–173. DOI:

Henry R, Dizhur D, Elwood K, Hare J, and Brunsdon D (2017). “Damage to concrete buildings with precast floors during the 2016 Kaikura earthquake”. Bulletin of the New Zealand Society for Earthquake Engineering, 50(2): 174– 186. DOI:

New Zealand Government (2016). “MBIE inves-tigation into building performance press release: (last accessed 20 Dec 2016)”.

MBIE (2017). “Investigation into the performance of Statis-tics House in the 14 November 2016 Kaikoura Earthquake”. URL: publications/building-and-construction/investigation-into-the-performance-of-statistics-house.pdf.

Wellington City Council (2016). “Earthquake Recovery Information Centre (ERIC) (last accessed: 20 Dec 2016)”.

Fairfax Media (2016). “"Building on Wellington’s Molesworth St being torn down". 28 November 2016 (last accessed 29 Nov 2016)”.

Fairfax Media (2016). “"Car park building and cinema at Queensgate Mall in Lower Hutt will be demolished" 26 November 2016 (last accessed 20 Dec 2016).”

Chandramohan R, Ma Q, Wotherspoon L, Bradley B, Nayy-erloo M, Uma SR, and Stephens M (2017). “Response of instrumented buildings under the 2016 Kaikoura earthquake”. Bulletin of the New Zealand Society for Earthquake Engi-neering, 50(2): 237–254. DOI:

Van Houtte C, Bannister S, Holden C, Bourguignon S, and McVerry G (2017). “The New Zealand Strong Motion Database”. Bulletin of the New Zealand Society for Earth-quake Engineering, 50(1): 1–20. DOI:

Kaiser A, Van Houtte C, Perrin N, Wotherspoon L, and McVerry G (2017). “Site characterisation of GeoNet stations for the New Zealand strong motion database”. Bulletin of the New Zealand Society for Earthquake Engineering, 50(1): 39–49. DOI:

Boon D, Perrin N, Dellow G, Van Dissen R, and Lukovic B (2011). “NZS1170.5:2004 Site subsoil classification of Lower Hutt”. 9th Pacific Conference on Earthquake Engi-neering: 8.

Semmens S, Perrin N, and Dellow G (2010). “It’s Our Fault - Geological and Geotechnical Characterisation of the Welling-ton Central Business District”. GNS Science Consultancy Report 2010/176.

Semmens S, Perrin N, Dellow G, and Van Dissen R (2011). “NZS1170.5:2004 site subsoil classification of Wellington City”. 9th Pacific Conference on Earthquake Engineering.

Langridge R, Van Dissen R, Rhoades D, Villamor P, Little T, Litchfield N, Clark K, and Clark D (2011). “Five Thousand Years of Surface Ruptures on the Wellington Fault, New Zealand: Implications for Recurrence and Fault Segmen-tation”. Bulletin of the Seismological Society of America, 101(5): 2088–2107, DOI: 10.1785/0120100340. DOI:

Fry B, Stephenson W, Benites R, and Barker P (2010). “It’s Our Fault : seismic instrumentation and inversion for phys-ical parameters of Wellington and the Hutt Valley”. GNS Science consultancy report 2010/18.

Van Dissen R and Berryman K (1996). “Surface rupture earthquakes over the last 1000 years in the Wellington re-gion, New Zealand, and implications for ground shaking hazard”. Journal of Geophysical Research, 101(B3): 5999– 6019.

NZS11705 (2004). “Structural design actions, Part 5: Earth-quake actions - New Zealand”: 82.

Kawase H (1996). “The Cause of the Damage Belt in Kobe: "The Basin-Edge Effect," Constructive Interference of the Direct S-Wave with the Basin-Induced Diffracted/Rayleigh Waves”. Seismological Research Letters, 67(5): 25–34, DOI: 10.1785/gssrl.67.5.25. DOI:

GeoNet (2016). “M 8.2 - 8.3, Wairarapa, 23 January 1855: ac-cessed: 15 Dec 2016)”.

Kaiser A, Holden C, Zhao J, McVerry G, and Benites R (2012). “It’s Our Fault: Ground motion modelling of local site effects in the Wellington region”. GNS Science consul-tancy report 2012/172.

Holden C, Kaiser A, Van Dissen R, and Jury R (2013). “Sources, ground motion and structural response character-istics in Wellington of the 2013 Cook Strait earthquakes”. Bulletin of the New Zealand Society for Earthquake Engi-neering, 46(4): 188–195. DOI:

Bradley B, Razafindrakoto HNT, and Nazer M (2017). “Strong ground motion observations of engineering inter-est from the 14 November 2016 Mw7.8 Kaikoura, New Zealand earthquake”. Bulletin of the New Zealand Society for Earthquake Engineering, 50(2): 85–93. DOI:

McVerry G (2011). “Site-effect terms as continuous func-tions of site period and Vs30”. 9th Pacific Conference on Earthquake Engineering: 8.

Chandramohan R, Baker JW, and Deierlein GG (2016). “Im-pact of hazard-consistent ground motion duration in struc-tural collapse risk assessment”. Earthquake Engineering and Structural Dynamics, 45(8): 1357–1379, DOI: 10.1002/eqe. 2711.

Chandramohan R, Baker JW, and Deierlein GG (2016). “Quantifying the Influence of Ground Motion Duration on Structural Collapse Capacity Using Spectrally Equivalent Records”. Earthquake Spectra, 32(2): 927–950, DOI: 10. 1193/122813EQS298MR2.

Raghunandan M and Liel AB (2013). “Effect of ground motion duration on earthquake-induced structural collapse”. Structural Safety, 41(0): 119–133, DOI: DOI:

Bommer J and Martinez-Pereira A (1999). “The effec-tive duration of earthquake strong motion”. Journal of Earthquake Engineering, 3(2): 127–172, DOI: 10.1080/ 13632469909350343.

Kempton J and Stewart J (2006). “Prediction equations for significant duration of earthquake ground motions consider-ing site and near-source effects”. Earthquake Spectra, 22(4): 985–1013, DOI: 10.1193/1.2358175. DOI:

Bommer JJ, Stafford PJ, and Alarcon JE (2009). “Empirical Equations for the Prediction of the Significant, Bracketed, and Uniform Duration of Earthquake Ground Motion”. Bul-letin of the Seismological Society of America, 99(6): 3217– 3233, DOI: 10.1785/0120080298. DOI:

Bradley BA (2011). “Correlation of Significant Duration with Amplitude and Cumulative Intensity Measures and Its Use in Ground Motion Selection”. Journal of Earthquake Engineering, 15(6): 809–832, DOI: 10.1080/13632469.2011. 557140, URL:

Bradley B (2012). “Ground Motion Comparison of the 2011 Tohoku, Japan and 2010-2011 Canterbury earthquakes: Im-plications for large events in New Zealand”: 8.

Graves RW, Pitarka A, and Somerville PG (1998). “Ground-motion amplification in the Santa Monica area: Effects of shallow basin-edge structure”. Bulletin of the Seismological Society of America, 88(5): 1224–1242, URL:

Adams BM, Osborne NM, and Taber JJ (2003). “The Basin-Edge Effect from Weak Ground Motions Across the Fault-Bounded Edge of the Lower Hutt Valley, New Zealand”. Bulletin of the Seismological Society of America, 93(6): 2703–2716, DOI: 10.1785/0120010277, URL:

Benites R and Olsen KB (2005). “Modeling Strong Ground Motion in the Wellington Metropolitan Area, New Zealand”. Bulletin of the Seismological Society of America, 95(6): 2180–2196, DOI: 10.1785/0120040223, URL:




How to Cite

Bradley, B. A., Wotherspoon, L. M., & Kaiser, A. E. (2017). Ground motion and site effect observations in the wellington region from the 2016 Mw7.8 Kaikōura, New Zealand earthquake. Bulletin of the New Zealand Society for Earthquake Engineering, 50(2), 94–105.