f Seismic applications of acoustic reciprocity

Progress in seismic data processing requires the knowledge of all the theoretical aspects of the acoustic wave theory. We choose the reciprocity theorem as the central theme, because it constitutes the fundaments of the seismic wave theory (Fokkema and van den Berg, 1993). In essence, two states are distinguished in this theorem. These can be completely different, although they share the same time -invariant domgin of application and they are related via an interaction quantity. The particular choice of the two states determines the acoustic application. This makes it possible to formulate the seismic experiment in terme of a geological system response to a known source function.