Why we have a policy
All Councils are required by legislation to have an earthquake prone building policy.
The Grey District is also in a zone of high seismic activity, with the Alpine and several lesser faults running through the District. Movement in the Alpine fault is likely within decades and is likely to have a significant impact on the District. In the Greymouth area, the ground shaking will be amplified by the risk of liquefaction (refer to Section 2.3 of the Lifelines Report which can be viewed in the Civil Defence section).
Whilst any policy does not serve as a guarantee that buildings will not be damaged or destroyed in an earthquake event, possibly causing injury to people in or around the building, this policy does endeavour to minimise some of the risk for and from buildings in an earthquake.
How the policy was developed
In developing the policy, Council had to balance the need to protect public health and safety against the economic implications of requiring significant remedial building work and the community's desire to protect historic structures and the West Coast heritage.
Because of the high seismicity and the presence in the district of several significant faults, and in spite of its relatively small size, Grey District Council has previously pursued a policy of encouraging the strengthening of earthquake-prone buildings through the building consent process.
Council also considered the following two key issues:
- The level of resilience which the Council and community want to achieve for the long term viability of the District.
- The level of hazard which can be tolerated over both the short and long term.
In considering these, Council needed to achieve a balance between a number of conflicting issues and concerns:
- The safety of the public when an earthquake event occurs.
- The likelihood, severity and potential timing of a major earthquake.
- The economic impact on the District of a major earthquake.
- The relative age and condition of non-residential buildings within the District.
- The costs of undertaking a comprehensive review of potentially earthquake- prone buildings and the availability of funding for this work.
- The costs to building owners of planned and progressive strengthening of buildings versus the economic impact of catastrophic failures caused by an earthquake and/or the potential economic impact (including loss of businesses) to the District where buildings are too costly to strengthen.
- The risk that buildings which are uneconomic to strengthen will be demolished and that the character of the built environment in Grey District will alter as a result.
- The potential loss of heritage buildings as the result of this process.
The adopted policy must reflect Council's approach to reduce earthquake risk over time, but in a way that is acceptable to its ratepayers.
Grey District Council adopted its initial earthquake-prone buildings policy in 2006 and adopted a revised version February 2011. Council subsequently adopted the current interim version on 13 May 2013 following the Government's announcement to eventually change the legislation for assessing and strengthening earthquake prone buildings.
The current policy is available below.
Earthquake-prone, Dangerous and Insanitary Buildings Policy (PDF, 9MB)