18 September 2017 Mark Easton - Principal Geotechnical Engineer

Mark EastonThe unpredictable nature of natural disasters requires the engineering community to be immediately thrown into shaping the future of the built environment, and the community which inhabits it. Since September 2010, the South Island of New Zealand has been impacted by a series of significant earthquakes and aftershocks. The most notable of these were the February 2011 and November 2016 events.  In general, key learnings from the 2011 event have been applied to the 2016 event. This resulted in significantly improved engineering response, at organisational, technical and operational levels.

The 2011 Christchurch earthquake caused significant issues with structural performance, ground liquefaction and landsliding. In response to these issues, the engineering community worked in a collaborative manner to collect, interpret and apply the learnings to engineer solutions that are pragmatic, proportional to the risk profile, offered an appropriate level of resilience and were sustainable.

This collaborative approach has bred a tight-knit engineering community, predominately through specific ‘working groups’.  As a result, a number of key engineering techniques and learnings relevant to the way in which engineers can better react to a natural disaster were developed.

The 2016 Kaikoura earthquake provided an opportunity for the previous five years of learnings to be effectively applied. Whilst the specific nature of the Kaikoura earthquake and its consequences were quite different from those of the Christchurch earthquake, the engineering process was similarly aligned and similar working arrangements were established more rapidly.

Over the Kaikoura coast, scores of significant landslides inundated both road and rail infrastructure, with fault ruptures and ground displacements adding to the damage. Road and rail term consultants worked in alliance, recruiting additional engineering resource to meet the high workload demands.

By the start of 2017, a design and build consortium, known as the North Canterbury Transport Infrastructure Recover (NCTIR) had been formed.  The knowledge retention due to a relatively short period of time between events enabled the Kaikoura recovery to proceed at an accelerated pace. The critical 25km of coastal transportation corridor remain on track for re-opening. A key factor of this recent success is the serendipitous occurrence of two significant natural disasters in a very short period of time and within a relatively localised geographic.

Natural disasters, by their very nature, tend to be low frequency but have high consequences. It is the low frequency element and the passing of time that can develop an element of complacency in those tasked with reacting when disaster strikes. Developing appropriate engineering response and recovery processes in ‘peace time’ to enable logical and collective working at points of stress were critical.  Controlling authorities should be encouraged to interface early with the engineering community to develop effective responses to the inevitable impact of natural hazards and improve the community’s resilience.