This paper explores key aspects of underground pipeline network response to the Canterbury earthquake sequence in Christchurch, New Zealand, including the response of the water and wastewater distribution systems to the MW6.2 22 February 2011 and MW6.0 13 June 2011 earthquakes, and the response of the gas distribution system to the MW7.1 4 September 2010 earthquake, as well as the 22 February and 13 June events. Repair rates, expressed as repairs/km, for different types of pipelines are evaluated relative to (1) the spatial distribution of peak ground velocity outside liquefaction areas and (2) the differential ground surface settlement and lateral ground strain within areas affected by liquefaction, calculated from high-resolution LiDAR survey data acquired before and after each main seismic event. The excellent performance of the gas distribution network is the result of highly ductile polyethylene pipelines. Lessons learned regarding the earthquake performance of underground lifeline systems are summarized.

The effects of transient and permanent ground deformations during the 22 February 2011 earthquake on the Christchurch water distribution system are investigated through geospatial analysis with the most detailed and accurate databases currently available. Using the most recent repair records, ground motion records, high resolution Light Detection and Ranging (LiDAR) data collected before and after the earthquake, and improved screening criteria, repair rates, expressed as repairs/km, for different types of pipeline are correlated with 1) peak ground velocity outside liquefaction areas, and 2) differential ground surface lateral and vertical movements in liquefaction areas. The substantial influence of LiDAR resolution on the relationship between pipeline damage and lateral ground strain indicates sensitivity of repair regressions to the degree of data resolution. Repair regressions of different pipelines show that polyvinyl chloride pipelines are markedly more resilient to earthquake effects than other types of segmental pipelines in the Christchurch system. The analytical process is described in detail for assistance in future investigations with data sets of similar size and complexity.

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