In this paper, the characteristics of near-fault ground motions recorded during the Mw7.1 Darfield and Mw 6.2 Christchurch earthquakes are examined and compared with existing empirical models. The characteristics of forward-directivity effects are first examined using a wavelet-based pulse-classification algorithm. This is followed by an assessment of the adequacy of empirical models which aim to capture the effect of directivity effects on amplifying the acceleration response spectra; and the period and peak velocity of the forward-directivity pulse. It is illustrated that broadband directivity models developed by Somerville et al. (1997) and Abrahamson (2000) generally under-predict the observed amplification of response spectral ordinates at longer vibration periods. In contrast, a recently developed narrowband model by Shahi and Baker (2011) provides significantly improved predictions by amplifying the response spectra within a small range of periods surrounding the directivity pulse period. Although the empirical predictions of the pulse period are generally favourable for the Christchurch earthquake, the observations from the Darfield earthquake are significantly under-predicted. The elongation in observed pulse periods is inferred as being a result of the soft sedimentary soils of the Canterbury basin. However, empirical predictions of the observed peak velocity associated with the directivity pulse are generally adequate for both events.
A video of a presentation by Dr Craig Davis of the Los Angeles Department of Water and Power on "Learning and planning collaboration on 'Earthquake-Flood Multi-Hazard Impact on Lifelines' and 'Resilience Measures and Strategies'". The presentation was delivered at the Learning from Lifeline Week and Planning Collaborations forum as part of the University of Canterbury's Lifeline Week.
A photograph of picket signs in the windows of the Earthquake Services building on the corner of Fitzgerald Avenue and Ferry Road. The signs read, "Welcome to EQC,. Your call is important to us...", "EQC: fool me once, shame on you...", "Pig brother is watching you", and "Another winter of discontent".
Road cones outside South New Brighton School have been decorated with flowers for the anniversary of the 22 February 2011 earthquake.
Prime Minister John Key at the memorial service held in Latimer Square on the anniversary of the 22 February 2011 earthquake.
The head of the Earthquake Commission is questioning why some Christchurch people are living in dire straits when there's help available.
Prime Minister John Key at the memorial service held in Latimer Square on the anniversary of the 22 February 2011 earthquake.
Road cones outside South New Brighton School have been decorated with flowers for the anniversary of the 22 February 2011 earthquake.
Flowers and feathers decorate a road cone on Estuary Road, New Brighton, on the anniversary of the 22 February 2011 earthquake.
A photograph of Jane Sutherland-Norton taken by Elise Rutherford as part of the "Biography, photography and women's earthquake stories" project.
An entry from Ruth Gardner's Blog for 25 October 2013 entitled, "Extra Exercise".
An entry from Ruth Gardner's Blog for 27 December 2013 entitled, "Regal Rooster".
An entry from Ruth Gardner's blog for 2 March 2013 entitled, "Supportive Smiles".
An entry from Ruth Gardner's blog for 20 January 2013 entitled, "Busking Brothers".
An entry from Ruth Gardner's blog for 30 January 2013 entitled, "Crossed Cranes".
An entry from Ruth Gardner's blog for 30 March 2013 entitled, "Advanced Aspect".
An entry from Ruth Gardner's blog for 22 January 2013 entitled, "Daddy in Danger?".
An entry from Ruth Gardner's blog for 16 April 2013 entitled, "Road Released?".
An entry from Ruth Gardner's blog for 26 June 2013 entitled, "Street Signs".
An entry from Ruth Gardner's blog for 17 April 2013 entitled, "Hanging Hearts".
An entry from Ruth Gardner's blog for 7 June 2013 entitled, "Red-zone Reductions".
An entry from Ruth Gardner's blog for 26 February 2013 entitled, "Popular Port-a-loos".
An entry from Ruth Gardner's blog for 28 June 2013 entitled, "Cordon cleared".
An entry from Ruth Gardner's blog for 12 June 2013 entitled, "Public Poem".
An entry from Ruth Gardner's blog for 30 May 2013 entitled, "Wintry Walking".
An entry from Ruth Gardner's blog for 18 January 2013 entitled, "Multiple Mowers".
An entry from Ruth Gardner's blog for 14 April 2013 entitled, "Restart Rhyme".
An entry from Roz Johnson's blog for 15 December 2013 entitled, "From the Ground Up part three".
An entry from Roz Johnson's blog for 15 December 2013 entitled, "From the Ground Up part one".
An entry from Roz Johnson's blog for 15 December 2013 entitled, "From the Ground Up part two".