Age of Electronics (1946-1970)Toward the Theory of Plate Tectonics
Three Great Tools of the 1960s
Cooperative Efforts in Ocean Research
Following World War II, the Coast and Geodetic Survey's operations returned to normal. A new type of navigation, known as Shoran, came to replace the older RAR (radio acoustic ranging); and electronic echosounding was the common system in use for delineating the bottom, although the lead line was still used to acquire least depths over possible obstructions to navigation. Tracklines to and from Alaska were still followed. A major development during this period was the Electronic Position Indicator (EPI), a navigation system developed by the Coast and Geodetic Survey that gave accuracies of approximately 100 ft at distances out to 200 mi from shore-based stations. Shoran, by comparison, was only good to 50 to 60 mi under the best of conditions. EPI was first tested and used in surveys in the Gulf of Mexico in 1947. In 1952, EPI was used in the Bering Sea, with the result that the true nature and extent of Bowers Bank, just north of the Aleutian Islands, became known for the first time.
Inevitably, EPI and Shoran were replaced by newer commercial navigation systems bearing names such as Raydist and Hi-Fix. EPI had a "last hurrah" in 1955, however, when the Coast and Geodetic Survey Ship Pioneer used it to survey the U.S. West Coast from San Diego to Cape Flattery. This was a Navy-funded survey in support of submarine warfare needs. The Navy required accurate bathymetry out to a few hundred miles offshore. Shortly into the project, the Scripps Institution of Oceanography requested that it be allowed to tow a newly developed marine magnetometer from the Pioneer. Permission was granted, leading to what the great marine geologist H.W. Menard called "one of the most significant geophysical surveys ever made." The Pioneer Survey, as it came to be called, discovered long, linear magnetic "stripes" on the sea floor. Ultimately, this striping led to the ability to date the age of the sea floor, as well as to compare magnetic patterns across fracture zones and from one side of an oceanic ridge to another. Because of these factors, the recognizable magnetic patterns associated with the sea floor were a major element in formulating the Theory of Plate Tectonics.
It only remained to put the pieces of the puzzle together. Harry Hess, of Princeton University, did this in the early 1960s, when he published his famous "essay in geopoetry," outlining the major elements of sea-floor creation at ridge crests, sea-floor destruction along the oceanic trenches, and the rafting of passive continents over mantle material of the Earth's interior. In the years since he presented this elegant concept, the evidence supporting it has grown at ever increasing rates. This one paper led to a whole new way of looking at the Earth as a unified system, relating the evolution of the sea floor as a key to understanding the distribution and evolution of the continents, the evolution and distribution of life on earth, and the evolution of present-day oceanic current and weather systems. The implications of Hess's theory for economic geology, as related to the distribution of resources, was also enormous. It had become clear that what happened in faraway seas, in far away times, did indeed affect all of us profoundly.
Hess's theory came at an opportune time in the history of ocean exploration. A few years earlier, the Committee on Oceanography of the National Academy of Sciences/National Research Council had issued its 1959 report during the Administration of President Eisenhower; then, President John F. Kennedy had called for a "national effort in the basic and applied research of oceanography." He noted that "Knowledge of the oceans is more than a matter of curiosity. Our very survival may hinge upon it." This statement referred to national defense needs, environmental concerns, and the wise extraction of resources from the sea. In such an atmosphere, oceanography and ocean exploration, like the parallel efforts of the space race, began to thrive.Three Great Tools of the 1960s
Three great tools of ocean exploration were developed during this period. The first was the Deep Tow instrument system, built and operated by the Scripps Institution of Oceanography. This tethered system was lowered from a surface vessel to just above the sea floor. The system was originally designed to obtain sea-floor slope information in the deep sea. Ultimately, it evolved into a system with multiple sensors for characterizing the deep-sea environment including a downward-looking, narrow-beam sounding system, a sidescan sonar system, television and still-camera systems, and a variety of other sensors and sampling devices. Bottom-mounted acoustic transponder navigation instruments were developed to support the relative navigation of the Deep Tow instrument within a study area. Virtually all deep-towed instrument packages ultimately trace their lineage to the Scripps system.
Multibeam sounding instruments were the second major development of this period. The first multibeam sounding system, known as the Sonar Array Sounding System (SASS), was installed on the U.S. Navy Ship Compass Island in 1963. Multibeam sounding systems obtain depths over a swath of bottom perpendicular to the heading of the survey ship, as well as directly below the ship (as in single-beam sounding systems). Such sounding arrays, coupled with accurate navigation, allow the immediate generation of accurate sea-floor maps. Multibeam sounding systems are now the de facto instrument for most mondern-day bathymetric mapping efforts.
Seamap and Other U.S. Initiatives
Other major developments in the 1960s included the U.S. Navy's ocean survey program; the C&GS's building of a fleet of new survey ships, including a number of ocean survey vessels; the building of a research fleet for the university community; and the C&GS's Seamap Project, initiated in 1961. The Seamap Project was started in response to the 1959 National Academy of Sciences report, and was notable because it was the first time that survey ships embarked on the specific mission of systematically mapping large areas of an oceanic basin (the North Pacific). Most tracks were oriented north-south and extended between the Aleutian Islands and the Hawaiian Islands; line spacing was 10 nm (nautical miles) between survey lines. Seamap ships observed an integrated suite of geophysical parameters, including bathymetry, gravity, and magnetics. The ships ran many thousands of miles of trackline before the project ended in the early 1970s. While new technologies and new requirements for accuracy have rendered these first efforts obsolete for most purposes, Seamap was a pioneering effort that proved the importance of such surveys.Cooperative Efforts in Ocean Research
In spite of the U.S. Government's relatively large investment in survey and research ships during this period, it was clear that exploration of the oceans required international cooperation. The Coast and Geodetic Survey participated in its first international cooperative effort in 1963. The project, EQUALANT, was a study of the equatorial Atlantic Ocean between Africa and South America. This was followed by the International Indian Ocean Expedition of 1964, and the C&GS Ship Oceanographer's around-the-world cruise of 1967. At the time, the Oceanographer was the newest and largest oceanographic ship in the U.S. research fleet.
The trend of international cooperation in ocean science was highlighted by President Lyndon Baines Johnson's 1968 proposal to launch an International Decade of Ocean Exploration in the 1970s. Not coincidentally, President Johnson had spoken at the Oceanographer's commissioning ceremony in July 1966, and Vice-President Hubert Humphrey, Chairman of the National Council on Marine Resources and Engineering Development, was the keynote speaker at the inception of its 1967 global cruise for the dual mission of science and goodwill.
The Stratton Commission and the Founding of NOAA
Perhaps it was no accident that BOMEX occurred at the same time that President Johnson assembled a group of outstanding men to study the problems our nation faced in managing and protecting the resources of the sea, as well as to determine areas how to best use our scientific and engineering resources to conduct ocean research. That commission, known as the Stratton Commission after its chairman, Julius Stratton, Chairman of the Ford Foundation, produced a report, " Our Nation and the Sea," which served as the blueprint for a new civil agency dedicated to describing and predicting changes in the Earth's environment, and conserving and wisely managing the nation's coastal and marine resources. President Richard M. Nixon spelled out the guiding philosophy for this newly envisioned agency in July 1970:"The oceans and atmosphere are interacting parts of the total environmental system upon which we depend, not only for the quality of our lives, but for life itself. "We face immediate and compelling needs for better protection of life and property from natural hazards, and for a better understanding of the total environment -- an understanding which will enable us more effectively to monitor and predict its actions, and ultimately, perhaps to exercise some degree of control over them. "We also face a compelling need for exploration and development leading to the intelligent use of our marine resources. We must understand the nature of these resources, and assure their development without either contaminating the marine environment or upsetting its balance. "Establishment of the National Oceanic and Atmospheric Administration -- NOAA -- within the Department of Commerce would enable us to approach these tasks in a coordinated way."
On October 3, 1970, this new agency, NOAA, came into being. A new era of ocean exploration had begun.