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Canterbury Liquefaction Information

Liquefaction is the process where, during earthquake shaking, sand and silt grains in wet soil are rearranged and the water in the spaces between the grains is squeezed.

Pressure builds up until the silt and sand grains float in the water, and the soil behaves more like a liquid than a solid. The pressurised water is forced up to the ground surface through the easiest path it can find - often through cracks and crevasses in the ground or concrete.

Liquefaction susceptibility maps have been produced for each district in Canterbury as part of earthquake hazard assessments for infrastructure (Kaikoura, Waimakariri, Selwyn, Ashburton, Mackenzie, Waimate and Waitaki) or as specific reports (Hurunui and Timaru).