What lies beneath

Liquefaction of soil can contribute to earthquake damage.

Earthquakes in New Zealand in recent years have heightened interest in understanding the risk of liquefaction and how the movement of different soils might influence earthquake damage. A better understanding of risk can help ensure that construction is appropriate to keep people safe in the event of an earthquake.

Auckland Council funded research into liquefaction risk by Omer Altaf, a lecturer at our Auckland International Campus in collaboration with engineering firm Tonkin & Taylor. With the firm's mapping database Omer used existing borehole and computation test data and Land Information New Zealand's Geotechnical Database to produce a high level regional map and report for the Council. He is also doing a similar exercise for Marlborough District Council for the Lower Wairau Plains. Further work is needed in Auckland on the performance of volcanic soils in an earthquake.

Once the map is finalised the Auckland Council's intention is for the data to be made publicly available. This will enable developers and the Council to make informed decisions about when more detailed site-specific investigation of liquefaction risk would be appropriate.

February 2020