A 3D 3C Shallow Seismic Refraction Survey Across a Shear Zone at Bungendore

Abstract

A three dimensional (3D) three component (3C) shallow seismic refraction survey was recorded across an extension of the Lake George fault in the butcher's paddock at Bungendore. The ANSIR equipment employed 348 channels in a static spread set out as 4 lines of 29 stations with 3 component geophones. The seismic energy source was a IVI Minivib, T15000. P- & S-wave sweeps were employed. Shear zones are an important concern in most geotechnical investigations. However, they can be especially difficult to separate from artifacts of inversion algorithms, because the traveltime anomalies are relatively small. Saline groundwater in major bedrock fractures, appears to be the source of dryland salinity in the Dubbo area. In other areas of dryland salinity, eg Wagga, the source is wind blown salt. Identifying the source of the salinisation is important in selecting the correct remediation strategy.