![]() ![]() “GroundMotion Observations from the 14 November 2016 Mw7.8 Kaikoura, New Zealand, Earthquake and Insights from Broadband Simulations”. Science, DOI: 10.1126/science.aam7194.īradley BA, Razafindrakoto HNT, and Polak V (2017). “Complex multifault rupture during the 2016 M w 7.8 Kaikura earthquake, New Zealand”. 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). Preliminary surface fault displacement measurements. “14th Novem-ber 2016 M7.8 Kaikoura Earthquake. 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). “The 2016 Kaikura, New Zealand, Earthquake: Preliminary Seismo-logical Report”. 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). 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. Such durations are slightly longer than the corresponding D s595 = 10s and 25s in central Christchurch during the 22 February 2011 M w6.2 and 4 September 2010 M w7.1 earthquakes, but significantly shorter than what might be expected for large subduction zone earthquakes that pose a hazard to the region. The 5-95% Significant Duration, D s595, of ground motions was on the order of 30 seconds, consistent with empirical models for this earthquake magnitude and source-to-site distance. 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 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. Several ground motion observations on rock provide significant constraint to understand the role of surficial site effects in the recorded ground motions. 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. The region was the principal urban area to be affected by the earthquake-induced ground motions from this event. This paper presents ground motion and site effect observations in the greater Wellington region from the 14 November 2016 M w7.8 Kaikōura earthquake. University of Auckland, Auckland, New Zealand University of Canterbury, Christchurch, New Zealand ![]()
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