Because Guam is a U. Commonwealth, the United States has jurisdiction over the Mariana Trench. In , President George W. Bush established the Mariana Trench Marine National Monument, which created a protected marine reserve for the approximately , square miles , square km of seafloor and waters surrounding the remote islands.
It includes most of the Mariana Trench, 21 underwater volcanoes and areas around three islands. The Mariana Trench was created by the process that occurs in a subduction zone , where two massive slabs of oceanic crust collide. At a subduction zone, one piece of oceanic crust is pushed and pulled underneath the other, sinking into the Earth's mantle, the layer under the crust.
Where the two pieces of crust intersect, a deep trench forms above the bend in the sinking crust. In this case, the Pacific Ocean crust is bending below the Philippine crust. The Pacific crust, also called a tectonic plate, is about million years old where it dives into the trench.
The Philippine plate is younger and smaller than the Pacific plate. As deep as the trench is, it is not the spot closest to the center of Earth. Because the planet bulges at the equator, the radius at the poles is about 16 miles 25 km less than the radius at the equator. The crushing water pressure on the floor of the trench is more than 8 tons per square inch kilograms per square meter.
This is more than 1, times the pressure felt at sea level, or the equivalent of having 50 jumbo jets piled on top of a person. A chain of volcanoes that rise above the ocean waves to form the Mariana Islands mirrors the crescent-shaped arc of the Mariana Trench. Interspersed with the islands are many strange undersea volcanoes. For example, the Eifuku submarine volcano spews liquid carbon dioxide from hydrothermal vents similar to chimneys.
The liquid coming out of these chimneys is degrees Fahrenheit degrees Celsius. Magnify that feeling by thousands and you can imagine how incredible the pressure would be in the Challenger Deep with almost 7 miles of water overhead. As challenging as it is to explore the Mariana Trench and the Challenger Deep in particular, several intrepid explorers have succeeded in this task.
The first recordings of the depth of the trench were made by the British Royal Navy Challenger expedition in , using a weighted rope, which recorded a depth of 4, fathoms 8, meters; 26, feet. In , the Japanese sent a survey vessel to the Trench to collect data using a multibeam echo sounder. The sound waves sent from the echo sounder bounce off the bottom of the ocean and are plotted on a graph to make a map of the ocean bottom.
This system allowed scientists to collect important environmental data without endangering a human diver. A multibeam sonar survey of the Mariana Trench by the University of New Hampshire found new seafloor features, and obtained the most precise measurement of Challenger Deep— 10, meters 6. This expedition collected data and specimens previously unknown, leading to a wealth of scientific knowledge about one of the least known parts of our Earth.
Along with a visual journey to the Mariana Trench, you can view a wealth of data related to the area, including multibeam bathymetry data and digital elevation models DEMs that illuminate seafloor features, such as seamounts and fault scarps. DEMs are a 3D representation of terrain, merging both land and seafloor.
With continued research into the deepest points of our ocean, the mysteries held in the Mariana Trench are slowly being revealed. Bathymetry, defined as the depth and shape of the seafloor, underpins the safe, sustainable, cost-effective execution of almost. Navy submersible. They were only able to spend 20 minutes there due to the extreme pressures, and their arrival stirred up too much dust from the seafloor for them to take any pictures.
Cameron was able to spend three hours there. And, of course, he captured video and took many photos—he is a Hollywood filmmaker, after all. The extreme pressures took a toll on his equipment, though. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Discover World-Changing Science.
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