what is the deepest point of the oceans?

Answer 1

Marianas Trench


So, How Do They Know?

In 1984 the Japanese sent a highly specialized survey vessel out the the Marianas Trench and collected some data using a piece of equipment called a narrow, multi-beam echo sounder.

What an echo sounder does is send high frequency sound waves (outside the range of human hearing) through the water down to the ocean bottom. Sound waves will travel through water, even faster than they travel through the air, and bounce off solid objects, such as the ocean bottom. The echo sounder measures precisely how long it takes for the sound waves to be returned to the surface and determines the depth based on the rate of return. These soundings are plotted on a graph by a computer to make an "echo map" of the ocean bottom.
The deepest measurement of the Challenger Deep currently available was taken by the Japanese and was found to be 35,838 feet.

The Mariana Trench (or Marianas Trench) is the deepest known submarine trench, and the deepest location in the Earth's crust itself. It is located in the floor of the western North Pacific Ocean, to the east and south of the Mariana Islands at 11°21′N 142°12′E, near Guam.

Submarine trench in the floor of the western North Pacific Ocean. It is the deepest known depression on the surface of the Earth, with a maximum depth of 36,201 ft (11,034 m). The trench extends from southeast of Guam to northwest of the Mariana Islands, a distance of more than 1,580 mi (2,550 km), and has a mean width of 43 mi (69 km).


Explore the Mariana Trench
The Mariana Trench is located in the Pacific Ocean, just east of the 14 Mariana Islands (11"21' North latitude and 142" 12' East longitude ) near Japan. As you probably already know, it is the deepest part of the earth's oceans, and the deepest location of the earth itself. It was created by ocean-to-ocean subduction, a phenomena in which a plate topped by oceanic crust is subducted beneath another plate topped by oceanic crust.

The deepest part of the Mariana Trench is the Challenger Deep, so named after the exploratory vessel HMS Challenger II; a fishing boat converted into a sea lab by Swiss scientist Jacques Piccard.

On this site, you will find information on the main characteristics of the Mariana Trench, its exploration, and its ecosystem.

The Biology section of the site covers the fish and various (organisms and microorganisms) of the deep, what makes these creatures unique, and the fascinating ways in which they live and survive.

The Oceanography section explores the data pertaining to the Mariana Trench and other deep sea formations.

The Exploration section relates some of the events pertaining to the first survey of the MT, and the history of deep sea exploration.

We have also included a section on the Mariana Arc, from an article published by NOAA (National Oceanic and Atmospheric Administration) Magazine Online. In addition to this, we also added a nautical measurement conversion table, so that you may

In closing we have added two supplemental sections so that you may continue your research into the fascinating world of the deep. Whether you are seeking answers to questions about the Mariana Trench, or are simply interested in Marine Biology, Oceanography, or related subjects, we hope our site will help you better understand the mysteries of the ocean floor.

Marianas trough, or Marianas deep (mâr´´n´z) (KEY) , elongated depression on the Pacific Ocean floor, 210 mi (338 km) SW of Guam. It is the deepest (35,798.6 ft/10,911.5 m at the Challenger Deep) known depression on the earth’s surface. A U.S. navy bathyscape reached its bottom in 1960; a 1995 Japanese probe made what is probably the most accurate measurement of its depth.

The depth of the Marianas trench has actually been known for some time. The trench is of course a long continuous feature running from Yap to the Bonin Islands, but I'll assume you mean the Challenger Deep, which is the deepest point along this trench. I will also apologize in advance for not having exact dates in front of me, but it goes something like this:



Echosounders have been used as oceanographic tools since the '60s. These work by sending a sound (or ping) out into the water and then listening for the echo. If you know how fast sound travels in sea water, then it's simply a matter of taking the time, T, it takes for the sound to go down to the seafloor and echo back and multiplying it by the sound velocity in seawater, V, which is about 1500 m/s. You also have to divide by 2 since what you're measuring is the total time of the trip of the ping to the seafloor and then back to the ship. Therefore to get distance, D, use:



D = 1/2 x V X T

or

D = 750 x T



And in this way the Challenger Deep was first determined to be the deepest point in the ocean back around 1960 or so. The name "Challenger" in fact comes from the name of the ship that identified this point. It's about 11 km deep, or just under seven miles, or about 36000 ft. When you fly in an airliner at cruising altitude you are as high above the ground as we are above the seafloor when we take the ship across the trench.

But the story doesn't end there. I think it was around 1962 or so that a submersible, the "Trieste", descended to the bottom of the trench with its inventor aboard, Jacques Piccard, and a US Navy lieutenant (sorry, forgot his name). Another way to determine depth is by measuring the water pressure which is the same as the weight of water above you, and all submersibles carry a pressure sensor.

But there is a problem with both techniques. The velocity of sound in water isn't constant at 1500 m/s, since sound velocity is dependent on density, salinity, and temperature of the water, things that all change from place to place and with depth. Pressure is also dependent on seawater density. The solution? You need an accurate measure of seawater velocity. This can be done by dropping a probe over the side of the ship that measures sound velocity as it descends and sends this data back to the ship by an attached wire. It doesn't go all the way to the bottom but since most of the change in seawater sound velocity is in the upper 100 meters (the thermocline) it doesn't have to. Modern sonar surveys use such a probe prior to conducting surveys to get accurate sound velocity and thus accurate depths.

I hope this answers your question. Let me know if you have any more.


Hope I Helped-CS


Aloha,

Nathan Becker
Department of Geology and Geophysics, University of Hawaii
1 year ago
Source(s):
http://en.wikipedia.org/wiki/Marianas_Tr...

http://www.extremescience.com/DeepestOce...

http://www.answers.com/topic/mariana-tre...

http://www.marianatrench.com/

http://www.bartleby.com/65/ma/Marianas.h...

http://www.utdallas.edu/dept/sci_ed/Melv...

Answer 2

Deepest point: 36,198 feet (11,033 m) in the Mariana Trench in the western Pacific

Answer 3

the core of the earth i guess, but then again if u drill through the core it will only get deeper and deeper and there u will get to the deepest point of the ocean which is infact the surface of the sea.

Answer 4

Kermadec Trench in the Pacific. I think.

Answer 5

I THINK IT IS THE MARIANAS TRENCH OFF THE COAST OF MINDINAO, PHILLIPINES. IT IS 11KM DEEP THE DEEPEST POINT ON EARTH.

Answer 6

I'm goin with the bottom!!

Answer 7

the bottom lol.

Answer 8

the bottom.

Answer 9

where it is the darkest