This data is intended to provide regional guidance for TLA land use planners in discriminating land where damaging liquefaction is unlikely from areas where geotechnical investigation is needed to assess liquefaction hazard. The areas are conservative in nature and should be used at an appropriate regional scale. They are not designed to be used at individual property scale. 

The reports and maps outline broad zones where liquefaction is more or less likely due to the general nature of the soils and water table in the area.  None of the reports or maps give the likelihood of liquefaction for a particular site or land parcel.  This is because soil types, and thus the tendency for liquefaction, can change a lot over very short distances - so soils on one property might be prone to liquefaction, while soils on the neighbouring property aren't.  To assess the liquefaction hazard for every single property in Canterbury would cost tens of millions of dollars.  Instead, these reports and maps show areas where liquefaction is less likely and special geotechnical assessment is not needed, and areas where liquefaction is more likely.  In these more likely areas a geotechnical assessment may be needed before building to assess more accurately how susceptible the soil is to liquefaction and what can be done to minimise any future damage from liquefaction.  In this way a geotechnical assessment for a particular site is only done where and when it is needed.

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