Abstract

About 70% of the Earth and much of its hydrocarbons are covered by water, but the ocean does not prevent us from using geophysical methods offshore. The ocean helps. Compared to land seismic surveys, marine is like looking under the lamp. Surface-towed seismic streamers are now the primary method for offshore geophysics, but before we had streamers, the only way to acquire geophysical data offshore was to put receivers on the seabed. Ocean-bottom cables and nodes started almost 80 years ago. Ewing, Wortzel, and Vine deployed autonomous ocean-bottom nodes they developed at Lehigh University. In independent efforts at that same time, Bullard, Gaskell, and Flavill used geophones on an ocean-bottom cable they developed at Cambridge University. The sources were dynamite. I do not know if any of these pioneering OBC and OBN surveys made it to the fledgling SEG. The young seismic industry was too busy with the challenges and opportunities of land seismic surveys to spare attention and talent offshore. The oil industry was focused onshore. The early ocean-bottom seismometers could not record a large amount of data and there was little interest in what they did record. Their usage was limited to academia, which has been using ocean-bottom nodes continuously since the 1930s.

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