The greatest damage from the major earthquakes in 2010 and 2011 occurred as a result of soil liquefaction, ground spreading and ground shaking. Some hill suburb houses were also badly affected by ground slumping or sliding, falling rocks and boulders, and falling cliffs.

Houses performed well overall, but there were exceptions where damage was significant:

  • houses with complex designs such as split-level design, irregular plan shapes, vertical irregularity or a mix of structural systems and stiffness
  • houses with heavy elements such as walls of solid unreinforced masonry (brick or concrete block) or brick chimneys
  • connection failures between structural and non-structural elements, to cladding attachments, and to the interface between original construction and more recent additions
  • unreinforced concrete slabs on ground
  • use of brittle steel reinforcing to foundations and slabs.