Earthquake performance of telecommunications infrastructure in Christchurch 2010 / 2011

Christchurch (population 350,000) New Zealand has suffered from three significant earthquakes in the last 12 months · September 4 2010 magnitude 7.1 (no fatalities) · February 22 2011 magnitude 6.3 (182 fatalities) · June 13 2011 magnitude 6.3 (no fatalities) Each earthquake had different centres and shaking characteristics. Telecom is the main provider of Fixed Line services in New Zealand. It also operates Mobile, Broadband, Data and other telecommunications services. Chorus is the business within Telecom that owns and operates the Access part of that network (cables and contractors that provision customer equipment) and operates the Buildings portfolio (including the power equipment) that houses the telecommunications equipment. This paper discusses the impact the earthquakes had on the Telecom network, the issues in maintaining and restoring services and some of the permanent fixes required to its infrastructure. The Telecom NZ core network continued to operate both through and after each event and the many aftershocks. There was call overloading issues on both the PSTN and Mobile networks, but much more significantly on the February 22 event that coincided with the mid-day lunch break. After the immediate aftermath panic, calling levels returned to manageable levels. Telephone exchange buildings, mobile cell towers and roadside access cabinets suffered minimal damage, compared to the very significant damage to other buildings in the CBD and eastern suburbs. All equipment (network, power and air conditioning) had been seismically supported and suffered no damage. Telecommunications power systems continued to operate as designed. There was widespread damage to the public power systems and in some areas it was more than a month following the February event before restoration was achieved. Most exchanges in the affected areas had engine alternators to support equipment loads. Mobil Cell Tower systems had batteries that would last greater than two hours and Access Cabinets (primarily installed to provide enhanced broadband services) had batteries to last greater than five hours. It was recognised from earlier events that the Mobile network would be the prime mode of telecommunications (for both restoration and normal communications); so many sites had been provisioned to be easily connected to portable engine alternators. Immediate restoration efforts were targeted at locating a sufficient number of suitably sized engine alternators, to keep these sites operational. Most had fibre connections back to a telephone exchange. Few cell sites failed. The next priority was refuelling on a regular basis. Many more issues were identified and managed through as efforts were made to restore some form of normality to the running of the city. Resources were available locally to manage most of the day to day restoration efforts but were significantly boosted by Chorus people operating remotely and some who travelled to the city to relieve the permanent residents as the event restoration stretched on. Other significant issues that became apparent were largely dependant on other infrastructure services to provide permanent solutions. These included the power system, water supply (for the cooling towers of the central exchange that formed part of the national network architecture) and access through damaged streets to some network nodes (mainly Mobile sites). The paper outlines details of both temporary and permanent restoration solutions.