Marine Seismic Prospecting

Abstract

IN the years immediately preceding the War, considerable progress was made in the use at sea of the seismic method of studying submarine geology, and work wascarried as far as the 100-fathom line. Further progresstodeeper water was rendered difficult by the troubles arising in putting the instruments and explosives on thebottom of the sea. As a result of work in 1938 and 1939, itwas suggested¹ that it might be possible to avoid these difficulties by having the instruments hanging in the water and relying on the transmission of the seismic waves from the bottom into the water. Unpublished observationsduring the War, both in Great Britain and in the United States, showed that seismic waves could, in fact, be observed in this way. In order to test the possibilities ofthe method, a direct comparison has been made of the signal received by a geophone on the bottom and by a hydrophone in the water. The explosive was also hanging in the water.