A team of scientists from GNS Science and the German Leibniz Institute for Applied Geophysics (LIAG) will utilise unique geophysical technology to attempt to image and better locate the Whakatāne Fault. 

The project, which will run in the Whakatāne urban area for 10 days from 12 February, is funded by EQC and is supported by the Whakatāne District Council and LIAG. It involves towing a 200 metre long ‘land streamer’ with an array of 96 seismic sensors behind a vehicle. The system will also be used to analyse the fault structure beneath McCracken Road, in the Edgecumbe area. That work will begin on 9 February and is expected to take three days.

The system receives acoustic signals generated by a small vibrating source placed near the land streamer array. The acoustic signals are reflected from various geological structures up to 100 metres below the surface. Measurements are made while the streamer is stationary, and after each set of measurements, the vehicle moves forward a short distance. Scientists estimate they will cover about 400 metres a day.

The survey will mostly be undertaken at night (between 8 pm and 6 am), both to reduce the impact on traffic flows and to minimise the potential ‘seismic noise’ generated by traffic and other daytime activities.

The scientists will acquire data along profiles oriented at right angles to the fault. The images created by the reflected waves will help to refine the location and geometry of the fault, especially in urban parts of Whakatāne, where it is hidden by alluvial gravels.

This technique has been used in Europe and Asia and is especially designed for use on paved roads, which makes it ideal for imaging the geological structures beneath urban environments. This will be the first time this technique has been used in New Zealand, and if successful it may be applied in other urban centres where concealed faults are known to exist.

The project will be led by Dr Christof Mueller from GNS Science and Dr Ulrich Polom from LIAG.