A Deep Sounding from the Southern Hemisphere

Abstract

IT is well known that the great trenches of the Western Pacific represent larger vertical departures from the level surface of the geoid than even the Himalayas. But our knowledge of the shape of the ocean floor is still so fragmentary that the question as to which trench is the deepest has received several different answers within the past two decades. The Mindanao Trench east of the Philippines was long believed to contain the greatest oceanic depth; but for a few years prior to 1950 many authorities considered that the U.S.S. Ramapo soundings in the Japan Trench were the deepest yet recorded. In that year Hess and Buell¹ re-examined the data and concluded that the sounding of 5,740 ± 50 fathoms obtained in the Mindanao Trench by the U.S.S. Cape Johnson during the Second World War represented tho greatest depth. H.M.S. Challenger in 1951 made still deeper soundings in the Marianas Trench east of Guam. These were reported by Carruthers and Lawford², and later Gaskell, Swallow and Ritchie³ stated that the maximum depth lay between 5,882 and 5,940 fathoms.