Botanic Gardens focus of quake study

The University of Canterbury is researching how soils react when an earthquake strikes, with a focus on Christchurch's Botanic Gardens.

Two new sensors are being installed in the gardens in the central city - one at ground level,  the other 30 metres below the surface - to enable the measurement of the ground’s movement between the devices. 

The Christchurch City Council and GNS Science are also involved in the project. 

GNS Science is responsible for installing the hi-tech equipment. 

Infrastructure specialist Tim McDougall says during a quake they expect the in-ground sensor, situated in the Riccarton gravels, will behave differently to the surface sensor, which is above material that can liquefy. 

It is the measurable movement between the two sensors that will reveal the nature of the liquefiable material in the earth - and that is of interest to scientists worldwide.

Mark Stringer, a senior lecturer at the university's Civil and Natural Resources Engineering Department,  says all that is needed now is a small quake, so researchers can begin to understand how shaking seen at the top site corresponds with shaking 30 metres below ground. 

“If we're able to predict what the ground motion will be in different parts of the city, we can start to understand what the design of a building should be to cope with the sideways shaking that it will experience."

- By John Spurdle  

- Public Interest Journalism funded through NZ On Air