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Our knowledge of the sea base has many gaps ; maps based on satellite data stop only the roughest of details . A scientific sail is using asdic to fill up in the moving-picture show along its path from South Africa to Chile .
Since a U.S. Navy research watercraft , the Melville , leave from Cape Town Feb. 20 , geophysicist Joseph " JJ " Becker has been map underwater mounts as tall as 14,800 base ( 4,500 meters ) , using asonarsystem that bounce sound off the seafloor and analyse the sign that returns . [ Image of submarine muckle ]
Using multibeam sonar, the research ship Melville charts undersea mountains.
The satellite data do n’t offer exact information about the height ofseafloor mountains , so for the work party of the Melville , passing over them can be tense . In one case , the artificial satellite datum predicted the peak of a quite a little would be 19.7 human foot ( 6 megabyte ) below the control surface . The ship draw almost the same astuteness . During the approach , Becker and the ship ’s headwaiter cautiously supervise the stack below them on the sonar to make indisputable they were n’t go to run aground . Meanwhile , someone else kept an eye out for rocks or shoal .
Even a sonar - notice astuteness of 984 feet ( 300 MB ) was cause for vexation in the open ocean , where some steeple could have gone chartless . " In real life , this is a chip like driving your car toward a brick bulwark , forecast how many seconds it will take to hit the rampart and being ready to slam on the bracken at the last minute , " Becker distinguish OurAmazingPlanet .
Rough ride
Using multibeam sonar, the research ship Melville charts undersea mountains.
As of Monday ( March 7 ) , the Melville had crossed the South Atlantic and was heading past the Falkland Islands . Unreachable by headphone , Becker answered motion by e - mail , although at one point on Friday ( March 4 ) , a rough sea forced him to cut short a reply .
" The boat was rocking about 20 degree to each way , 40 total . That ’s enough that even if you are sitting in a chair , the death chair can decrease over , so I had to give it a rest , " Becker publish .
Only about 7 per centum of thedeep oceanhas been mapped using ship data point , agree to David Sandwell , a prof of geophysics at the Scripps Institution of Oceanography in California . Sandwell tweaked the Melville ’s route to take it above an interesting - look area en route to Valparaiso in central Chile .
The ship’s sonar system transmits sound into the water beneath it and analyzes the signal that returns to map the ocean floor.
" Take one of our ships with a multibeam echo sounder " – the sonar system . " It would take 125 years to map the deep sea basin completely , " Sandwell say . " So you could see the problem here , it ’s just a vast field and ships go slowly . "
oceanographer use satellite measurements of the build of the sea ’s surface to make a rough picture of the sea floor . Large features under the ocean are massive enough to change the gravity field at the surface , pull in water and make bumps in the sea open . Satellite radar can find these excrescence and dips , Sandwell explained .
demand the longsighted way
The principal point of this voyage is to get the Melville , which is operate by Scripps , from Cape Town to Valparaiso , where it will foot up other researchers captive on studying the effects of last year’sChilean earthquakeon the seafloor . for make the best of the transit trip , Scripps populated the ship with scientist , including Becker .
About six months ago , Sandwell start project the ship ’s route , forge a racecourse that deviated slightly , by 3 pct , from the most direct route . Bad weather as they left Cape Town forced Scripps to retool the track assembly line , but it is equally interesting to the first , Sandwell said .
Becker compared it to pull up stakes Interstate 80 during your crusade from San Francisco to New York to see sites like Yellowstone .
" I intend the of import message is that if we can get the research ships to take even a 20 - naut mi roundabout way on a 5,000 - nautical mile voyage [ 32 klick on top of 8,050 km ] , we will attain endless new feature article ; seamounts , valleys and things we ca n’t imagine , " Becker drop a line .
you may followLiveScienceseniorwriter Wynne Parry on Twitter@Wynne_Parry .
