Geotechnical Reconnaissance of the 2011 Christchurch, New Zealand Earthquake

Edited by Misko Cubrinovski, Russell A. Green, and Liam Wotherspoon.

August 15, 2011. Geotechnical Extreme Events Reconnaissance.

The 22 February 2011, Mw6.2-6.3 Christchurch earthquake is the most costly earthquake to affect New Zealand, causing 181 fatalities and severely damaging thousands of residential and commercial buildings, and a significant portion of the city lifelines and infrastructure. However, the scientific and engineering significance of this earthquake goes well beyond the effects of this event alone, because the same region was impacted by an Mw7.1 Darfield six months earlier. Accordingly, there is much that can be learned from comparing the different levels of soil liquefaction, differing magnitudes and seismic source distances, and variable performance of buildings, lifelines, and engineered systems during these two earthquakes, along with the many strong aftershocks. It is rare to have the opportunity to document the effects of one significant earthquake on a modern city with good building codes. It is extremely rare to have the opportunity to learn how the same ground and infrastructure responded to two significant earthquakes. This report presents an overview of observed geotechnical aspects of the Christchurch earthquake.