The New Zealand S0ciety of Earthquake Engineers (NZSEE) have made available to the public copies of their Bulletins 43/4 for Dec 2010 (Darfield earthquake) and 44/4  for Dec 2011 (Lyttelton earthquake).

NZSEE is providing free access to download individual papers from these two Special Edition Bulletins (Financial support to publish the Bulletins has been provided by EQC):

http://www.nzsee.org.nz/bulletin_index/43_4.htm     

and

 http://www.nzsee.org.nz/bulletin_index/44_4.htm

Their website is here.