Robert L Fisher, PhD



Dr. Robert L. Fisher, now research geologist emeritus at UCSD’s Scripps Institution of Oceanography (SIO), was one of six San Diego Explorers Club Chapter founders in 1989 – 1990 and its Chair in 2000 – 2001. As a sea-struck and publishing academic he has made a huge and unique contribution to geological – geophysical knowledge of the world’s oceanic trenches, their evolution, and the crustal structure beneath the Pacific and Indian Oceans; the name “Bob Fisher” is synonymous with deepest seafloor exploration for half a century. 

Of more interest to the adventuring Explorers Club is his August 1959 use of innovative sounding techniques, very low ship speed, and several dozen half-pound TNT demolition blocks to the deepest axial basin in Challenger Deep in the Mariana Trench, 10,913± 15 meters, nearly 7 miles, in preparation for the January 1960 descent to the bottom there of Don Walsh and Engineer/Inventor Jacques Piccard in the bathyscaph Trieste. In late 1952 Bob had sounded Horizon Deep in the Tonga Trench to be – barely, at 10,800± meters –  the world’s second deepest. His underway program in SIO’s 1959 two-ship geophysical exploration throughout the Gulf of California produced the detailed bathymetric portrayal that revealed the plate tectonic aspects of that seismically-active region’s structural development.  In the mid 1960’s – 1984 Bob dredged fresh igneous specimens and photographed rough outcrops of hard rocks of the lower crust / upper mantle on deepest nearshore or petrologically distinct offshore flanks of three major Western Pacific trenches and from the precipitous abyssal fracture zones of the Southwest Indian Ocean. 

Between 1952 and 1985 an adventuring academic Bob Fisher planned and led major portions of 16 complex international collaborative marine geological/geophysical expeditions, three circling the globe, the longest 83,000 nautical miles in track.

Dr. Fisher received a B.S. in Geology from Caltech in 1949, and his doctorate – on trench geological / geophysical studies off western Mexico and Central America – jointly from SIO and UCLA in April, 1957. In 2004 Bob Fisher received the inaugural Drake Medal from Monaco based peers in recognition of his nearly six decades of meticulous seafloor cartography.  Its medallion in silver, now pewter, had been awarded once before, in 1584, by Queen Elizabeth I to Drake himself.


A Fellow of the Explorers Club since 1988, in 2003 Bob was elected an Honorary Member, joining the likes of John Glenn and Jim Whittaker.  In 2019 he was honored with the Explorers Club Lowell Thomas Award. In his profession 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. Less fleetingly, perhaps, in recognition of his contributions to deepest-sea geology-geophysics, some years ago the international seafloor nomenclature panel formally named a wholly-submerged Sierra Nevada-scale mountain range far south of Madagascar the “Bob Fisher Ridge”.

Three Honorary Members - Davis, Walsh &