Saunders, W.S.A.; Berryman, K.R. 2012 Just add water : when should liquefaction be considered in land use planning?. Lower Hutt: GNS Science. GNS Science miscellaneous series 47 13 p.
Abstract: Many local authorities are currently investigating liquefaction hazard and exploring land use planning methods to mitigate potential risk. While in many cases the need to investigate liquefaction hazard is required, anecdotal evidence indicates that several councils are unduly concerned with liquefaction risk. This is because liquefaction requires the following basic conditions in order to occur: an earthquake large enough to trigger liquefaction within planning timeframes; specific soil characteristics; and a high water table. The purpose of this report is to provide guidance to land use planners and decision makers so they can assess whether liquefaction is a hazard that needs to be included in the planning process. To achieve this, the report provides an explanation of liquefaction and earthquake thresholds (quantified by peak ground acceleration), followed by a simple decision tree designed for planners to ensure that liquefaction is appropriately included in land use planning decisions. Each of the steps in the decision tree is discussed in further detail. Key questions include: Are the soils susceptible to liquefaction? Are the consequences of liquefaction significant? What is the likelihood of an earthquake generating ground motions at a site above a liquefaction threshold of 0.1g peak ground acceleration occurring? Concluding the report is an overview of future research into liquefaction and its management. This report does not provide guidance on how to include liquefaction into planning documents – additional multi-disciplinary guidance to assist with this is being developed through other research and policy. (auth)