AbstractThe region of Graus (Central Spanish Pyrenees) has been surveyed by the conventional seismic reflection method in the years 1963–64.This region is strongly accidented and there are only a few roads of access. Thus a good grid of seismic lines could not be realised. Therefore a seismic survey with completely portable equipment was tried out. For that reason drilling was abandoned.The results seem to show that the method of the air‐shots is completely comparable with that of buried sh