The Challenger Deep

marina trench
The Deepest Ocean Area – The Challenger Deep

“…we have better maps of the surface of Mars and the moon than we do the bottom of the ocean. We know very, very little about most of the ocean.” Gene Feldman.

The Challenger Deep is the deepest recorded area in all the world to date.  The Challenger Deep is an area found at the southern end of the crescent-shaped Mariana Trench in the Western Pacific Ocean.  This oceanic trench lies approximately 124 miles east of the Mariana Islands.

The Mariana Trench

The Mariana Trench has been formed by subduction.  Subduction is when  techtonic plates meet and one plates is forced underneath another.  In the case of the Mariana Trench, the faster moving Pacific Plate, moving in a westerly direction is being forced under the slower moving Philippine Plate.  The western edge of the Pacific Plate contains some of the oldest crust and mantle on earth.  This makes the plate heavier and denser than the Philippine Plate.  The Philippine Plate, therefore, rides higher than the Pacific Plate which means the Pacific Plates is pushed under and the downward flexure forms a trough or trench.

The Challenger deep

HMS Challenger

The Challenger Deep was first discovered in 1875 by the Royal Navy research vessel HMS Challenger.  Challenger was tasked with carrying out the first global maritime research expedition, a 3.5 year, 69,000 nautical mile voyage.  Using just hemp line with iron sinkers attached to the end, they plumbed a depth of 4,475 fathoms (8,184 m or 26850 ft) in the southern area of what is now known as the Mariana Trench.

HMS challenger

Fast forward to 1951 and another HMS Challenger takes a depth reading in the same area of 5960 fathoms (10,900 m or 35761 ft) using echo sounding. The area is named Challenger Deep after this vessel.  The last recorded depth at Challenger Deep was taken on 2010 by the United States Center for Coastal & Ocean Mapping.  They recorded a depth of 10,994 meters (36,070 ff or 6011 fathoms) below sea level with an estimated vertical accuracy of ± 40 metres.

In old money that’s 7 miles deep.  For comparison Mount Everest is 5.5 miles high from sea level.  The pressure in this Hadal zone is in excess of an eye popping 16000 psi.  The atmospheric pressure in your home is about 14.7 psi.  These enormous pressures are the main reason it has been so difficult to explore these deep regions of the ocean.

Images Credits:

Image of Deep Ocean Trench – Credit otlibrary.com

Map of Challenger Deep location in the Mariana Trench Credit: COSEE-TEK/Google Earth

HMS Challenger – Credit North Wind Picture Archives/Alamy)

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