This article is about the oceanic trench. For the band, please see Marianas Trench (band).

Location of the Mariana Trench

The Mariana Trench (or Marianas Trench) is the deepest part of the world's oceans, and the deepest location on the surface of the Earth's crust. It has a maximum depth of about 11 km (6.8 mi), and is located in the western North Pacific Ocean, to the east and south of the Mariana Islands, near Guam.

The trench forms the boundary between two tectonic plates, where the Pacific Plate is subducted beneath the Philippine Plate. The bottom of the trench is farther below sea level than Mount Everest is above it (8,848m/29,028ft). At the bottom, the water column above exerts a pressure of 108.6 MPa, over one thousand times the standard atmospheric pressure at sea level.

Measurement and study

Cross-section of Mariana Trench, NOAA image

See also: Challenger Deep

The trench was first surveyed in 1951 by the Royal Navy vessel Challenger, which gave its name to the deepest part of the trench, the Challenger Deep.The Mariana Trench - Exploration. marianatrench.com. Retrieved on 2007-07-04. Using echo sounding, the Challenger II measured a depth of 5,960 fathoms (10,900 metres, 35,760 ft) at 11°19′N, 142°15′E.Ritchie, Steve. The deepest depths. Retrieved on 2007-07-04.

In 1957, the Soviet vessel Vityaz reported a depth of 11,034 meters (36,200 ft), dubbed the Mariana Hollow. "Mariana Trench". Encyclopædia Britannica. Encyclopædia Britannica. Retrieved on 2008-02-25.  (Although this claim was made by the Soviets in 1957, the finding has not been repeated by subsequent mapping expeditions using more accurate and modern equipment.^{[citation needed]})

In 1962, the surfac

ship M.V. Spencer F. Baird recorded a greatest depth of 10,915 meters (35,810 ft), using precision depth gauges. The deepest depths

In 1984, the Japanese sent the Takuy� (拓洋), a highly specialized survey vessel, to the Mariana Trench and collected data using a narrow, multi-beam echo sounder; they reported a maximum depth of 10,924 meters, also reported as 10,920 meters ± 10 meters).New Chief Hydrographer of Japan. Retrieved on 2007-07-04.

Descents

January 23, 1960: Trieste just before the dive

In an unprecedented dive, the United States Navy bathyscaphe Trieste reached the bottom at 1:06 p.m. on January 23, 1960, with U.S. Navy Lieutenant Don Walsh and Jacques Piccard on board. Iron shot was used for ballast, with gasoline for buoyancy. The onboard systems indicated a depth of 11,521 meters (37,799 ft), but this was later revised to 10,916 meters (35,813 ft).^{[citation needed]} At the bottom, Walsh and Piccard were surprised to discover soles or flounder about 30 cm (1 ft)long,National Oceanic and Atmospheric Administration (NOAA) webpage. Section "1960 - Man at the Deepest Depth" as well as shrimp.^{[citation needed]} According to Piccard, "The bottom appeared light and clear, a waste of firm diatomaceous ooze".

The most accurate measurement on record was taken by a Japanese probe, KaikÅ� (ã�‹ã�„ã�“ã�†), which descended unmanned to the bottom of the trench on March 24, 1995 and recorded a depth of 10,911 meters (35,798 ft).Japan Atlas: Japan Marine Science and Technology Center. Retrieved on 2007-07-04.

The Woods Hole Oceanographic Institution is planning to send its Nereus hybrid remotely operated vehicle (HROV) to explore the trench in 2008.Vessels and vehicles of the Woods Hole Oceanographic Institution

References

See also

• Oceanic trench
• Izu-Ogasawara Trench
• Yap Trench

Coordinates: 11°21′N, 142°12′E

This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia

This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia