Seismic refraction measurements in the Atlantic Ocean Basin (Part one)

A reversed seismic refraction measurement was made 120 miles northwest of Bermuda (400 miles east of Cape Hatteras) in 2,800 fathoms of water. A velocity of 24,800 feet per second (7.58 km/sec.) for the second layer was identified with the ultrabasic layer of earthquake seismology. Assuming a velocity of 5,600 feet per second (1.70 km/sec.), clearly indicated by earlier measurements, a thickness of 4,500 feet was obtained for the sedimentary layer. The granitic and intermediate layers were absent.