TRex arrives in town to shake things up

The world’s largest seismic vibration truck has touched down in Christchurch to test the city’s soil.

The 29-tonne truck, known as TRex, arrived from the United States last week to take part in a collaborative research project between the University of Canterbury (UC) and University of Texas, Austin.

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

The tests involve 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 United States.

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

‘‘The ground motion recorded in the February 22, 2011, earthquake illustrated significant basin effects. These were caused by reverberations of the soft sedimentary soils that Christchurch is founded on,’’ Bradley said.

The data would help researchers understand the effect of soil properties on ground movement during earthquakes.

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


  • The Press
  • Ashleigh Stewart
  • Photos: Kirk Hargreaves/Fairfax NZ

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