Measurement of electromagnetic effects generated by swell

Many studies have been conducted on swell, some of which have been particularly concerned with its associated magnetic field. One of us (M.K.) has reconsidered some of the theoretical studies which have been made, with attention given to the practical case of an ocean of finite depth.In the marine magnetotelluric program on the continental shelf, the Geophysical Research Center at Garchy has obtained records of the variation of the magnetic-field components in an ocean twenty meters deep.After having presented the hypothesis of the theoretical calculation, we give some computer-drawn chart (P.L.) and some power-density spectra of records obtained in the Mediterranean Sea. Some recent results on the electric field permits us to conclude that these first results are due to the magnetic field associated with swell and we discuss some implications of these results.