Seismic Geophysical Methods in Archaeological Prospection

Geophysical methods (as a non-destructive method) have been used in archaeological prospecting since the 1940s. The geophysical techniques that are most commonly used are electrical methods, magnetic, electromagnetic soil-conductivity systems and ground penetrating radar (GPR). Less commonly used methods include microgravity and seismic techniques. Most commonly, the geophysical survey is used to create maps for the detection of subsurface archaeological features. The features are recognized as lineaments in the geophysical image or due to regular shapes, thickness and geometrical characteristics of the resulting geophysical anomalies/signals. Geophysical instruments can detect buried features when their physical properties contrast measurably with their surroundings. Geophysical images can be used to guide archaeologists for planning excavations and to give them insights into the patterning of nonexplored parts of the site under investigation. Unlike other archaeological methods, geophysical survey is neither invasive nor destructive. For this reason, it is often used where preservation (rather than excavation) is the goal, and to avoid disturbance of culturally sensitive sites. The main purpose of this work is to present a review of the application of seismic methods to archaeology. Geophysicists have experimented with refraction seismic methods in archaeological applications with limited success, since refraction methods work best in mapping undisturbed layers that have velocities increasing with depth. The method becomes less useful and interpretation becomes very qualitative and difficult when there are velocity inversions representative of human cultural disturbance or highly three-dimensional objects such as burial sites or stone foundations. Nowadays new sensors, acquisition systems, processing/simulation techniques and configurations are adopted to overcome any complexity and to help the archaeologists map in an efficient way the subsurface.