If there's any low-hanging fruit in quake-strengthening, it's unreinforced masonry facades, parapets, and chimneys. They tend to fall outwards from buildings onto passers by. Tieing them back can be pretty cheap relative to other earthquake strengthening. And, there's a much stronger market failure case for addressing parts of buildings that will fall on top of passers-by than those that will fall onto the building's owner or tenants.
The NBR quotes Ann Brower:
The owner of the building next to the one that fell on her bus had strapped its façade and parapet: “His building hurt no one,” Ms Brower says.It's worth making sure that our heritage regulations are not making this kind of strengthening work impracticable.
But the owner of the three adjoining addresses hadn’t been required to do the same after the September 2010 quake and so hadn’t done so.
The Canterbury Earthquakes Royal Commission’s (CERC) report suggests “that no masonry building with tie-backs, bolts or any form of retrofitting killed anyone in Christchurch.”