Using the ground-penetrating radar to assess the conservation condition of rock-art sites

We present the results of a ground-penetrating-radar survey of the conservation condition of two rock-art sites in the KwaZulu-Natal Drakensberg (South Africa). The investigation depth in the local sandstone is comprised between 4 and 80 cm, which is enough to determine whether the rock walls present any fissures that could make them unstable. The radar therefore allows the localisation of possible weakness areas and a precise mapping of the conservation state of the rock-art sites. Areas ready to detach can be recognised and the depth of alteration zones at the major discontinuities can be assessed. The non-destructive and easy-to-carry ground-penetrating radar appears as a tool particularly adapted to rock-art conservation investigations.