ENERGY‐INTERACTION: THE LONG‐RANGE INTERACTION OF SEISMIC SOURCES¹

Abstract

LAWS, R., PARKES, G. and HATTON, L. 1988. Energy-interaction: the long-range interaction of seismic sources. Geophysical Prospecting 36, 333-348.The quantity of energy that is radiated as sound by marine seismic sources is examined. When more than one source is used, the total radiated acoustic energy depends on the separation of the sources and is not constant, even when the separation is sufficiently large that the individual signatures are substantially unaffected. We believe that this long-range interaction has not been described before in the literature and have called it energyinteraction.The existence of energy-interaction is demonstrated experimentally for airguns. In the experiment presented, the acoustic output is more than doubled because of energyinteraction.Two methods are described for computing the energy of the wavefield of an array of sources. One method is simple and direct; the energy that is radiated into the far field is calculated by integrating the directivity pattern over all directions. The other method finds the energy that is radiated into the near field. Because the medium is assumed lossless, these two energies are the same. Although the near-field method is conceptually more difficult, it is faster, more accurate and provides a more detailed description of the energy budget.