Neptune's Needle

Geophysicist and administrator.

Using seismic refraction techniques, Ewing showed that the crust beneath the ocean floor is considerably thinner than that beneath Earth's continents and composed of different materials, a major discovery about Earth's structure. In 1940 he took leave from Lehigh to pursue war-related research at the Woods Hole Oceanographic Institution in Massachusetts, then accepted a 1944 offer to join Columbia University's Department of Geology, where he was encouraged to build a program in geophysics.

Ewing is best known for two major contributions; a wide range of studies across the component fields of geophysics and his role in founding and leading the Lamont Geological Observatory, one of the most successful research schools of earth science in the twentieth century. While Ewing contributed simultaneously to several fields of geophysics, his research followed several distinctive patterns. During World War II he discovered the SOFAR (Sound Fixing and Ranging) channel in the ocean, a layer where sound energy remains trapped, allowing sounds (such as explosions) to be heard hundreds of miles away; this would become the basis of a major research program in undersea acoustics for the U.S. Navy early in the Cold War. In the late 1940s Ewing worked with Frank Press and others to develop a new theoretical interpretation of how surface waves propagate from earthquakes; he also began exploring the sediment deposits of ocean floors. After Columbia University purchased the three-masted schooner Vema for his use, Ewing began long ocean voyages and, with Bruce Heezen and Marie Tharp, studied the topography and distribution of earthquakes associated with the mid-ocean ridges; the three demonstrated that these ridges form a vast and nearly unbroken system circling the planet.

Ewing also gained a reputation as an expert instrument designer. During World War II he improved for the U.S. Navy a deep sea bottom camera used to probe undersea wrecks and the ocean floor and produced the first reliable model of the bathythermograph, a device used to rapidly measure temperatures and depths in the ocean. Later he helped design the Precision Depth Recorder, which provided for the first time a detailed and extremely accurate profile of the ocean floor. In the 1950s, with Frank Press, he also developed a new long-period seismograph, and made significant improvements to a device called the piston corer, which allowed fellow Lamont-Doherty researchers to obtain sediment cores from numerous locations throughout the ocean floor, eventually resulting in an unparalleled collection in Lamont's core laboratory.

Sources

Related People

Related Ships

Related Locations

Compiler

Peter Richards