Surface seismic includes all investigation methods implying seismic energy production on surface. Among these methods, the most important ones are represented by refraction and reflection seismic.

Seismic refraction is a consolidated method for subsurface investigation based on the analysis of P refracted first breaks. Their conversion into a subsurface velocity model can be accomplished by either conventional methods (GRM, Plus-Minus) or more sophisticated tomographic inversion algorithms.

This method is generally used to determine the sliding surface of landslides, to detect lithologic boundaries and to evaluate the degree of fracturation of rocks. It can also find application in environmental studies, to evaluate, for example, the rubbish thickness in dumps.

Esso trova applicazione anche negli studi di carattere ambientale per la valutazione dello spessore dei rifiuti nelle discariche.

Seismic reflection represents a technique for subsurface investigation based on rock elastic properties (acoustic impedance). Every surface marking a lithologic transition, no matter if it is stratigraphic or tectonic, represents an elastic discontinuity able to reflect upward the seismic energy propagating into the ground.

Reflected signals, recorded on the surface by geophones, are subsequently processed in order to produce seismic sections whose interpretation provides information about the structural setting of the investigated area.

The main advantages of this method can be summarized as follows:

• high depths of investigation using low energy sources and short geophone cables
• efficient method for interpolation and extrapolation of "point" information (boreholes)
• relatively limited costs
• negligible environmental impact