Acknowledgments

Joe Dellinger wishes to thank the Stanford Exploration Project for providing computer resources, which were accessible to him via the NSFnet trans-Pacific fiber-optic cable HAW-4. Lev Vernik wishes to thank Amos Nur for support. John Etgen wrote the modeling programs we used, and contributed his invaluable expertise when we were puzzled trying to interpret some of the finer details of the results. The authors wish to thank Leon Thomsen for many useful comments. This paper will be submitted to GEOPHYSICS as a SOEST publication. Sorry about the fanged S's in the figures: it's the printer being ``creative'' in its interpretation of postscript!