Research Geologist Emeritus
Geosciences Research Division

Robert L. Fisher is a research geologist emeritus in the Geosciences Research Division at Scripps Institution of Oceanography, University of California, San Diego. Fisher’s name has been synonymous with seafloor exploration for half a century. He has made monumental contributions to the scientific knowledge of seafloor trenches and the composition, crustal structure, and actual topography underlying the Pacific and Indian oceans.

Fisher was born (1925) in Alhambra, Calif. He received his BS at CalTech (1949) and his PhD from Scripps-UCLA in 1957.

He has organized and/or led 16 major multi-program, deep-sea expeditions since joining Scripps. In the 1950’s Fisher used sound-train echo analysis from subsurface TNT-block detonations and increasingly precise echo-sounder equipment to determine the near-bottom morphology and maximum depth of all of the major trenches in the Pacific and Indian oceans. He established the deepest point in the oceans, 10,915±10m, the Challenger Deep southwest of Guam in the Mariana Trench in 1959.

During Scripps’ major geological and geophysical expeditions, Fisher and colleagues – using Scripps open-ocean fleet – uncovered, refined, and published evidence of spreading seafloor and – notably – what is now called “subduction” and began to assemble early, jigsaw clues to plate tectonics. Accompanied at sea by Scripp seismologists Russell Raitt or George Shor, Bob Fisher clearly demonstrated that the igneous ocean crust descended diagonally below the continental crust on the landward or island-arc side of the Eastern Pacific (1954, 1958) and Indian Ocean (1960) trenches. In a 1963 review paper, he and Princeton University co-author Harry Hess extended and evaluated these observations.

During the late 1950’s Second International Geophysical Year, Scripps provided her R/V Horizon and R/V Spencer F. Baird on three expeditions to the East Equatorial and Southeast Pacific. Fisher was co-leader of the two-ship geological-geophysical reconnaissance named DOWNWIND (1957-8). Lessons learned in international sea-based operations for multi-ship field exploration were then employed for the 20-nation, 60-ship SCOR-promoted INTERNATIONAL INDIAN OCEAN EXPEDITION (IIOE, 1959-65). In that UNESCO-coordinated collaboration Scripps was a major institutional field contributor, primarily in deep-sea topography (trench and mid-ocean ridges), crustal structure (seismic refraction), magnetic profiling and heat flow measurements, but also physical oceanography (equatorial undercurrent: John Knauss) and ocean-wide plankton distribution and classification. Bob Fisher was overall director of the Scripps IIOE 1959-65 program and co-chair (with USSR’s P.L. Bezrukov) of SCOR’s IIOE Marine Geology, Geophysics and Bathymetry panel. As such he planned and led IIOE-shipboard research/explorations in 1960-61, 1962-63, and derivative follow-up Scripps cruises there in 1968-69, 1970-71, 1976, and 1984. Fisher made only one DSDP cruise in the Indian Ocean, as co-chief on Leg 24, Djibouti to Mauritius, in 1972.

Fisher was associate director of Scripps for Ship Operations and Marine Technical Support from 1974 to 1980.

From the mid-1960’s to mid-1970’s, Bob Fisher teamed with USGS chemist Celeste Engel, to make key plutonic igneous petrological discoveries in Tonga Trench and the western Indian Ocean’s ridges’ fracture zones. These results were made possible by development of ultra-strong 3/8 inch steel cable and the “Edgerton pinger” to permit near-bottom hovering (photography) and precise on-off bottom contact (dredging). Fisher and Engel dredged, described, and analyzed markedly fresh rocks from the lower crust and upper mantle that until then has been recovered nowhere else in oceanic locales. To honor his contributions to understanding such enigmatic regions of the seafloor, his international colleagues named a wholly submarine mountain range south of Madagascar the “Bob Fisher Ridge.”

In recognition of his extensive and meticulous work in ocean-bottom cartography over the past six decades, in 2004 Fisher was awarded the inaugural Drake Medal by the Monaco-based General Bathymetric Chart of the Oceans (GEBCO) organization. This award was created specifically to honor Fisher and is a replica of the medal given to Sir Francis Drake in 1589 by England’s Queen Elizabeth I to reward his monumental circumnavigation of the globe during the previous decade.

A fellow of the Explorer’s Club, Bob Fisher was elected an honorary member in 2004. He is a fellow of the American Geophysical Union and the Geological Society of America and an honorary life member of the United Kingdom’s Challenger Society. He also belongs to Sigma Xi and the American Association for the Advancement of Science.

Last updated October 2012