The 2010-2012 Canterbury Earthquake Sequence: pushing the limits of geological seismology using backyard science

The Canterbury earthquake sequence (CES) started with the 2010 moment magnitude (Mw) 7.1 Darfield earthquake and includes thousands of Mw ≥ 3 aftershocks, most notably the fatal 22 February Mw 6.2 Christchurch earthquake.

Dr Quigley described how the largest CES earthquakes caused geologic and geomorphic processes that changed the Canterbury landscape. Some of these changes lasted only hours and others will persist in the geologic record for thousands to millions of years or longer.

Using numerous examples, he described how careful documentation of the geomorphic and geologic effects of the Canterbury earthquake sequence, and comparing these with instrumental seismic data, is important because it helps to define the seismic thresholds for generating these phenomena and it enables paleoseismologists to better interpret these features when they are observed in the geologic record.

Dr Quigley’s heavily illustrated talk summarised the impacts of the Canterbury earthquake sequence and showed new evidence for the timing, extent, and conditions of prehistoric earthquakes in the Canterbury region, including penultimate rupture on the Greendale Fault, prehistoric liquefaction in eastern Christchurch, and prehistoric rockfall in the Port Hills south of Christchurch.

Better attention to the geologic record will help us to avoid further land planning mistakes and increase societal and financial resilience to future earthquakes both in Christchurch and elsewhere in New Zealand.

Dr. Mark C. Quigley is Senior Lecturer in Active Tectonics and Geomorphology in the Department of Geological Sciences at the University of Canterbury. www.drquigs.com/