Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Trevor Behr
Mapping Ocean Floors
As a species, humans have held onto a strong sense of curiosity
throughout the short time they have existed on this planet called Earth.
Through that curiosity they have discovered fire, created nuclear energy, and
cured mass epidemic diseases and all of these discoveries had a specific set of
directions leading them. It is for this curiosity that humans have plans
on how to build great skyscrapers and how to tie one’s own shoes, but the
greatest map of all time has yet to be completed. The earliest remnants of
modern day humans chalk up to being about 200,000 years old and our recorded
civilization being only 6,000 years of that, one would think there would be
somewhat of a complete map of the planet they exist on (Howell).
In fact, humans actually only have about one third of the entire
Earth’s surfaces mapped. This is calculated by knowing that the continents
and land masses of Earth have been 90% explored, leaving places like the Amazon
Rainforest, Antarctica, and large deserts to still be discovered. With the
largest missing piece being that people have only explored and mapped about 5%
of the entire ocean (Peters). Being that the ocean makes up 70% of the
Earth, leads us back to the notion that only about 30.5% of Earth has been
mapped thus far.
The task of mapping the ocean floor seemed simple in theory, but the
combined efforts of geologists and measurements from ship sonar and satellite
graphing still struggled to create a completely accurate map. This turned
to be so challenging that people had known more features of the Moon than they
did their planet’s own ocean. A group of geophysicist had set out to
correct such a notion, with the aid of U.S. Navy’s satellites and ships and
partnership with the National Oceanic and Atmospheric Administration (NOAA).
Their idea was to use the satellites to help measure the amount of gravitation
tension surrounding all parts of the Earth. From those measurements they
would predict depths of the ocean is specific areas and double check and correct
those measurements with the sonar from the Navy’s ships.
Gravitational pressure on the ocean (NASA). 2014
Since satellites could not sense the bottom of the ocean, microwaves
were bounced off the ocean’s surface to measure the body of water’s shape.
This would put in place both the distance from Earth the satellite was and what
portion of the Earth the satellite was viewing. Before being able to
measure the depths of the entire ocean through satellites, scientists only
mapped major shipping and travel routes between continents using hydrography.
Hydrography, by definition, is being the science of surveying and charting
bodies of water. A part of the surveying process called bathymetry was
used to map the inner most edges of continents for ship traffic by using sonar.
This same method was also used to double check the satellite gravity readings.
“Bathymetry map of East Flower Garden Bank” (NOAA).
Knowing more of how the ocean floor is structured helps scientists
predict and study continental drift and plate tectonics more thoroughly.
Since the undersea mapping had begun the NOAA has continued their discoveries
and researching into things such as lithospheric structure, mapping of undersea
volcanoes, and mining exploration of petroleum (Sandwell). Of course this
mapping process will also help to further identify changes in sea levels and the
identification of possible new landmasses.
There are still some problems with current ocean mapping, such as
that satellites cannot recognize ocean features smaller than 12 kilometers
across. This still puts a lot of guess work into mapping, David Monahan
explains this, “It's like drawing a map of a city, where you know a lot about
one street, then nothing for 10 miles, then a lot about another street”
(Mackenzie). Another example would be that, you know one street has
buildings on it, and three streets down has building on it, so you would assume
that in between these two points the other streets should have buildings.
In conclusion, underwater mapping has yet to be near to completion, but has made great efforts to do so. As people strive to go further into space and Mars, people will also try to reach deeper depths closer to our planet’s core. The more technologically advanced the human race becomes, the more they will learn of the planet they call home. One day there should be a complete map of Earth as scientists and exploiters continues to discover new hidden spaces of the planet. It is said that since the mapping of our oceans that the total space covered may soon be up to 15% (Fox).
Fox, Paul J. "Upheaval from the Abyss: Ocean Floor Mapping and the Earth Science
" Bulletin of the American Meteorological Society 84.5 (2003): 671-4.
ProQuest. Web. 21 Nov. 2016.
Howell, Elizabeth. "How Long Have Humans Been On Earth? - Universe Today."
Universe Today. N.p., 23 Dec. 2015. Web. 21 Nov. 2016.
Mackenzie, Dana. "Ocean Floor is Laid Bare by New Satellite Data." Science
1921. ProQuest. Web. 21 Nov. 2016.
NASA. "Seafloor Features Are Revealed by the Gravity Field." NASA. NASA, 29 Dec.
Web. 21 Nov. 2016.
Peters, Colleen. "The Ocean: Haven't We Already Mapped It? - Schmidt Ocean
Schmidt Ocean Institute. N.p., 12 Mar. 2013. Web. 21 Nov. 2016.
Sandwell, David T. "Estimated and Predicted Sea Floor Topography from Satellite
National Centers For Environmental Information. U.S. Department of Commerce, 1995.
Web. 21 Nov. 2016.