3-D georadar surveying in areas of moderate topographic relief

A three-dimensional (3-D) georadar survey has been conducted across a 41.2 × 34.5 m area with moderate topographic relief (dips: 4 - 16°) near Randa in southwestern Switzerland. For this survey, we employed a semiautomated acquisition system that combined a standard georadar unit with a self-tracking theodolite. This system recorded georadar data and coordinates simultaneously. Subsequently, an accurate topographic model of the acquisition surface was determined from the measured coordinates. With the aid of this topographic model, a provisional static correction for each georadar trace was determined. Application of the static corrections removed the most significant distortions of the major reflections and diffractions, which likely originated from the soil-rock interface and/or major fractures.