Five Deepest Ocean Trenches: Deep Plunges in Pacific Ocean Hadal Zone

Summary: The world's five deepest ocean trenches all occur in the Pacific. All plunge to depths deeper than Earth's highest landform, Mount Everest, is high.

Pacific Ring of Fire includes world's five deepest ocean trenches: Gringer, Public Domain, via Wikimedia Commons

The five deepest ocean trenches all line the western reaches of the Pacific Ocean, the largest of the world’s oceanic divisions. Subdivided into North Pacific and South Pacific at the equator, the Pacific has a north-south stretch from the Arctic Ocean to the Antarctic, or Southern, Ocean and east-west boundaries of the Americas and of Asia to Australia, respectively. Three of the deepest trenches are found in the western North Pacific while two slash the floor of the western South Pacific.

Ocean trenches are formed as long, steep, V-shaped depressions by the subduction, or pushing down, of an older, denser piece of Earth’s crust and uppermost mantle, known as a tectonic plate, by a lighter, younger plate. Comprising the deepest 45 percent of the world’s oceans, trenches occur in the hadal (pronunciation: haydl), or hadopelagic, zone, the layer of the ocean named after Hades (Ancient Greek: ᾍδης, Hāídēs), Greek god of the underworld.

The five deepest ocean trenches all plunge dramatically in the Pacific Ocean hadal zone. The deepest, the Mariana Trench in western North Pacific Ocean, has a maximum depth of 36,069 feet (10,994 meters), plus/minus 131 feet (40 meters). In second place, Tonga Trench in western South Pacific Ocean has a maximum depth of 35,702 feet (10,882 meters). Third-place Philippine Trench in western North Pacific Ocean has a maximum depth of 34,596 feet (10,545 meters). The fourth deepest oceanic trench, Kuril-Kamchatka Trench in western North Pacific Ocean, has a maximum depth of 34,587 feet (10,542 meters). In fifth place, Kermadec Trench in western South Pacific Ocean has a maximum depth of 32,963 feet (10,047 meters).

Known as Earth’s deepest abyss, Mariana Trench measures a depth that plunges 7,040 miles (2,146 meters) deeper into the seafloor than the soaring, 29,029-mile (8,848-meter) reaches into the atmosphere of the highest point on land, Mount Everest. The deepest part occurs in Challenger Deep, a small valley at Mariana Trench’s southern end. Mariana Islands, the trench’s nearby namesake, form an arc-shaped archipelago of 15 volcanic mountains on the eastern limit of the Philippine Sea.

Tonga Trench forms a north-northeast seafloor frame to its namesake 177-island archipelago, the Polynesian Kingdom of Tonga, that marks about one-third of the distance between New Zealand and Hawaii. The trench’s deepest point, Horizon Deep, occurs in the central area, north of Tonga’s collision with the lengthy Louisville seamount chain and outmeasures Mount Everest by 6,673 feet (2,034 meters).

Philippine Trench trends with a northwest-southeast orientation from Luzon, northernmost island in the archipelagic Republic of the Philippines, southward to Indonesia’s northern Maluku island of Halmahera. The deepest point, Galathea Depth, occurs in the trench’s southern region and overshoots Mount Everest by 5,567 feet (1,697 meters).

Kuril-Kamchatka Trench slices the seafloor with a northeast-southwest orientation between its namesakes, Kamchatka Peninsula and Kuril Islands in Russia’s Far East. The trench’s greatest depth surpasses Mount Everest’s height by 5,558 feet (1,694 meters).

Kermadec Trench traces a southwest-northeast orientation in its run from near the northeastern tip of New Zealand’s North Island, along namesake Kermadec Islands, to its endpoint northeast of Monowai Seamount. The trench’s deepest point exceeds Mount Everest’s lofty heights by 3,934 feet (1,199 meters).

Far below the surface of the waters of the vast Pacific Ocean, Earth’s five deepest ocean trenches plummet to dizzying depths below the seafloor. Sinking to depths far deeper than Mount Everest’s height, the five deepest ocean trenches present rigorous, almost insurmountable challenges to exploration and shelter vast mysteries concerning life amid extreme conditions.

size comparison of Challenger Deep with Mount Everest: Nauman from Karachi, Pakistan (Nomi887), CC BY SA 3.0, via Wikimedia Commons

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Pacific Ring of Fire: Gringer, Public Domain, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Pacific_Ring_of_Fire.svg

size comparison of Challenger Deep with Mount Everest: Nauman from Karachi, Pakistan (Nomi887), CC BY SA 3.0, via Wikimedia Commons @ https://commons.wikimedia.org/wiki/File:Challenger_deep_size_comparison_Mt_Everest.JPG

For further information:

Marriner, Derdriu. "Kermadec Ocean Sanctuary to Protect 240K Square Miles of South Pacific." Earth and Space News. Wednesday, Sept. 30, 2015.
Available @ https://earth-and-space-news.blogspot.com/2015/09/kermadec-ocean-sanctuary-to-protect.html