It is only in the last century that a fair measure of success was achieved by man in exploring the ocean floor and in discovering the details of its topographic features. Considerable help was received by the invention and continuing refinement of sonic depth finding instruments, which are capable of making continuous recordings of ocean depths by the use of reflected sound waves.
As a result of the unimaginable progress in the field of science and technology, man has at his disposal such sophisticated devices as the Scripps Oceanographic Institute’s deep sea drilling ship, the Glomar Challenger, and deep diving vehicles like the Trieste, which has reached down to a depth of 11 km below the sea level.
Until the most recent exploration of the oceans and seas, people believed that a large part of the ocean bottom comprised flat plains. Presently this cannot be accepted as it is far from the truth. As a matter of fact, the ocean floor is characterized by such irregularities in its land surface as are found on the continents.
M.F. Maury, one of the founders of oceanography, published the first bathymetric charts in 1854 that covered the Atlantic Ocean from 10°S to 52°N. Later on, concerted efforts were made to get information regarding the relief of the ocean bottom, not only for scientific reasons but also because of its practical applications.
The most important event in this matter was the establishment of the first Trans Atlantic cable connection between Newfoundland and Ireland in 1858. However, prior to the laying of the cable preliminary soundings had been taken to find the most convenient path for it.
The first experimental physical, chemical and biological investigations in the deep sea were undertaken in 1868 and 1869-1870 by the English ships namely, Lightning and Porcupine in the North Atlantic Ocean by Sir Wyville Thompson.
Later on, he organized the historic voyage of the Challenger (1872-1876) into the Atlantic, the Pacific, and the Indian Oceans. That was the most extensive oceanographic expedition ever made.
At the same time, similar work was done by the German Vessel Gazelle, though it was not as comprehensive as the Challenger Expedition.
In 1919, A. Behm made more reliable echo soundings solving many technical problems. The American Vessel, Stewart, in 1922, undertook the test of taking the first profile between the United States and Gibraltar.
Later on, in 1925-1927, the German vessel Meteor took the first systematic sounding in the South Atlantic Ocean. However, despite the vast amount of new soundings taken by means of echo sounding, the knowledge of the bottom relief of all the oceans remained scanty.
Later on, a new technique was developed which is known as wire sounding. It was superior to the echo sounding technique because it could provide samples of the ocean bottom.
In the recent past, a large number of bathymetric and nautical charts were published which increased the knowledge of the bottom relief of the oceans. In 1935, Stocks and Wust published the bathymetric charts of the oceans.
Besides, the International Hydrographic Bureau of Monaco also published similar charts of the world oceans on the scale of 1:10,000,000.
All these charts show that there is a remarkable regularity of the bottom relief among a multitude of topographic forms.