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Challenger Deep

earth science Maturity 7-9 Next article →

The Challenger Deep is the deepest known point of the Earth's seabed.

Marianatrenchmap
Marianatrenchmap

It is located in the western Pacific Ocean. This spot sits at the southern end of the Mariana Trench. The area is within the ocean territory of the Federated States of Micronesia. Scientists study this depression to understand the extreme limits of our planet. It is a vital site for oceanography and deep-sea research.

GEBCO 2019 bathymetry Challenger Deep and Sirena Deep
GEBCO 2019 bathymetry Challenger Deep and Sirena Deep

The topography of the Challenger Deep is quite specific. It is a small, slot-shaped depression. This slot exists inside a much larger, crescent-shaped oceanic trench. The floor of the Deep consists of three distinct basins. These basins are long, wide, and very deep. They are arranged in an echelon pattern from west to east.

Challenger Deep EM124 Sonar Map and Diving History 101119
Challenger Deep EM124 Sonar Map and Diving History 101119

Mounds of rock separate these three basins. The western and eastern basins both have recorded depths exceeding 10,000 meters. The center basin is slightly shallower than the others. Detailed sonar mapping shows the basins undulate with slopes and rock piles. These sit upon a bed of pelagic ooze, which is soft sediment.

Cross section of mariana trench
Cross section of mariana trench

Measuring the depth of such a massive area is a complex process. Hydrographers use multibeam echosounder systems to map the floor. These systems send acoustic pulses down to the seabed. However, the accuracy of these measurements depends on many factors. The speed of sound in water is not constant. It changes based on the water's bulk modulus, mass, and density. The bulk modulus is affected by temperature, pressure, and salinity. Scientists must correct for these variations to get precise data.

Hakuho Maru, Fremantle, 2019 (06)
Hakuho Maru, Fremantle, 2019 (06)

The history of discovering this site began in the late 19th century. In 1875, the British Royal Navy survey ship HMS Challenger found the area. The crew was traveling from the Bismarck Archipelago toward Japan. Baffling winds pushed the ship west of Guam. This accidental path took them over the massive undersea canyon. They used Baillie-weighted marked ropes to take depth soundings. They recorded a depth of 4,475 fathoms at station #225. This was the deepest sounding of their three-year voyage.

Gaskell HMS Challenger II
Gaskell HMS Challenger II

Another ship helped establish the record-setting depths later on. The HMS Challenger II conducted a survey from 1950 to 1952. This vessel used seismic-sized bomb-soundings and a taut wire method. To find the depth, they used a wire with 140 pounds of scrap iron. The weight took about ninety minutes to reach the bottom. This expedition discovered a large area deeper than 8,000 meters. This area was later identified as the western basin. The name "Challenger Deep" was adopted after this voyage to honor both ships.

Bathyscaphe Trieste
Bathyscaphe Trieste

In 1959, the research vessel Stranger provided definitive verification of the site. Dr. R. L. Fisher led this expedition using explosive soundings. The Stranger recorded a maximum depth of 10,911 meters. This survey helped the U.S. Navy plan the first manned descent. In January 1960, the bathyscaphe Trieste made the first successful descent. The Trieste was a specialized vehicle designed for extreme pressure. Since that historic dive, only 27 people have ever reached the bottom.

Bathyscaphe Trieste Piccard-Walsh
Bathyscaphe Trieste Piccard-Walsh

Modern science continues to refine our knowledge of these depths. A 2011 study placed the depth at 10,994 meters. A 2021 study revised this value to 10,935 meters at a 95% confidence level. These measurements rely on advanced technology like the DSSV Pressure Drop. This vessel uses the Kongsberg SIMRAD EM124 multibeam echosounder. Such work connects the Challenger Deep to the broader study of plate tectonics and ocean chemistry. The Deep remains one of the most mysterious and challenging environments on Earth.

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🖼️ Images & Media (23)
File:Marianatrenchmap.png
Marianatrenchmap.png
File:Challenger Deep EM124 Sonar Map and Diving History 101119.jpg
Challenger Deep EM124 Sonar Map and...
File:Gaskell HMS Challenger II.jpg
Gaskell HMS Challenger II.jpg
File:Kaliningrad 05-2017 img62 Ocean Museum.jpg
Kaliningrad 05-2017 img62 Ocean Museum.jpg
File:Cross section of mariana trench.svg
Cross section of mariana trench.svg
File:Hakuho Maru, Fremantle, 2019 (06).jpg
Hakuho Maru, Fremantle, 2019 (06).jpg
File:JAMSTEC Yokosuka P5123676.jpg
JAMSTEC Yokosuka P5123676.jpg
File:JAMSTEC Deep Sea Research Ship Kairei P7214312.jpg
JAMSTEC Deep Sea Research Ship Kairei P7214312.jpg
File:RV Melville (25635910745).jpg
RV Melville (25635910745).jpg
File:US Navy 090814-N-0000X-001 The Office of Naval Research small waterplane area twin-hull oceanographic research ship R-V Kilo Moana takes part in the second Radiance in a Dynamic Ocean (RaDyO) program.jpg
US Navy 090814-N-0000X-001 The Office of...
File:JAMSTEC Deep Sea Research Ship Kairei P7224519.jpg
JAMSTEC Deep Sea Research Ship Kairei P7224519.jpg
File:USCGC Sequoia (WLB-215).jpg
USCGC Sequoia (WLB-215).jpg

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