Harry Hess

Harry Hammond Hess (1906-1969) was an American geologist and Princeton University professor whose work helped explain the movement of the ocean floor. While serving as a United States Navy officer during World War II, he used echo-sounding equipment to investigate submarine features. These observations contributed to his developing account of ocean basins, linking naval surveying with a major question in Earth science. Hess circulated his seafloor-spreading hypothesis before publishing History of Ocean Basins in 1962.

He proposed that new oceanic crust forms along mid-ocean ridges and moves outward, with older crust eventually descending at ocean trenches. This supplied a mechanism essential to the later theory of plate tectonics. Independent paleomagnetic research, including the explanation of ocean-floor magnetic stripes, helped confirm the model. His work marks a connection between field observations and a testable account of continental movement.