P669 ELASTODYNAMIC RECIPROCITY THEOREMS FOR TIME-LAPSE SEISMIC METHODS JACOB FOKKEMA 1 KEES WAPENAAR 1 MENNO DILLEN 1 and KARIN SCHALKWIJK 2 1 Section of Applied Geophysics Centre for Technical Geoscience Delft University of Technology The Netherlands 2 Section of Seismics and Acoustics Centre for Technical Geoscience Delft University of Technology The Netherlands Introduction Reciprocity theorems play an important role in formulating true amplitude operations on seismic wave fields such as multiple elimination migration and characterization. In general a reciprocity theorem interrelates the quantities that characterize two admissible physical states that could occur in one and the same domain (de Hoop