TRex to shake up Christchurch

04:31, Mar 11 2013
t-rex landscape
T-REX: The worlds largest seismic vibration truck tests soil at Lyttelton Port.

The world's largest seismic vibration truck has arrived in Christchurch to test the city's soil.

The 29 tonne truck, known as "TRex'', arrived from the United States last week as a collaborative research project between the University of Canterbury (UC) and University of Texas, Austin, to test the ground around the city.

Testing began today in Lyttelton and the truck will visit 14 more sites around Christchurch before the end of the month.

It will be carried out by applying small vibrations to the ground, to determine the properties of soils up to 250 metres deep.

This is the first time the machine has been used outside the US.

UC earthquake engineer Dr Brendon Bradley said an understanding of Christchurch's soil properties at great depths was important because it impacted how seismic waves were amplified, reflected, and refracted as they travelled up to the earth's surface. 


''The ground motion recorded in the February 11 2011 earthquake illustrated significant basin-effects. These were caused by reverberations of the soft sedimentary soils that Christchurch is founded on. 

''Using state of the art information on soil properties throughout Christchurch obtained by TRex and previous testing we can begin to link cause and effect and better understand where such effects will occur elsewhere during future earthquakes worldwide,'' he said.

The public are invited to witness testing on Thursday at QEII Park and on March 21 at Ilam Fields at the University of Canterbury.

TRex will be in the country until at least May when UC researchers are hoping to use the truck to carry out testing on liquefaction. 

Researchers from the University of Texas said vibrations produced by the truck would not be felt from more than 15m away.

The Press