Tag: Oceanography

Structures under water

ocean - Major subdivisions of the oceans | Britannica

Oceanography is one of the largest areas of geography as it deals with the largest form on earth, Ocean. More than half of the earth’s surface is covered with water and it mainly consists of oceans. Even though it looks similar when we look from above, there are deep structures inside the water. Just like the land forms we daily see around us; oceans also have a wide variety of structures. In order to gain a clear idea about those, let us look into it in detail:

Major structures

Continental shelf

A continental shelf is the edge of a continent that lies under the ocean. Continents are the seven main divisions of land on Earth. A continental shelf extends from the coastline of a continent to a drop-off point called the shelf break. From the break, the shelf descends toward the deep ocean floor in what is called the continental slope. Even though they are underwater, continental shelves are part of the continent. The widths of the continental shelves vary.

Continental shelf

Continental slopes are regions of steeply sloping seafloor that lie between continental shelves and the deep ocean basins. Regional gradients are typically 2–5°, but locally slopes may be much steeper. Their large-scale morphology is a consequence of tectonic processes: the different elevations of continental crust and oceanic crust, the details of the original rift tectonics on passive continental margins, and the styles of subduction and accretion on convergent margins.

Continental rise

continental rise, a major depositional regime in oceans made up of thick sequences of continental material that accumulate between the continental slope and the abyssal plain. Continental rises form as a result of three sedimentary processes: mass wasting, the deposition from contour currents, and the vertical settling of clastic and biogenic particles.

Abyssal plane

The term ‘abyssal plain’ refers to a flat region of the ocean floor, usually at the base of a continental rise, where slope is less than 1:1000. It represents the deepest and flat part of the ocean floor lying between 4000 and 6500 m deep

Minor structures

Abyssal hills

An abyssal hill is a small hill that rises from the floor of an abyssal plain. They are the most abundant geomorphic structures on the planet Earth, covering more than 30% of the ocean floors. Abyssal hills have relatively sharply defined edges and climb to heights of no more than a few hundred meters. They can be from a few hundred meters to kilometers in width.

Trenches

Ocean trenches are steep depressions in the deepest parts of the ocean, where old ocean crust from one tectonic plate is pushed beneath another plate, raising mountains, causing earthquakes, and forming volcanoes on the seafloor and on land.

Submarine canyons

A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to 5 km, from canyon floor to canyon rim, as with the Great Bahama Canyon.

Ocean has several other wonders hid under its deep waters. If we go deeper new structures unfold.

Structures under water

ocean - Major subdivisions of the oceans | Britannica

Oceanography is one of the largest areas of geography as it deals with the largest form on earth, Ocean. More than half of the earth’s surface is covered with water and it mainly consists of oceans. Even though it looks similar when we look from above, there are deep structures inside the water. Just like the land forms we daily see around us; oceans also have a wide variety of structures. In order to gain a clear idea about those, let us look into it in detail:

Major structures

Continental shelf

A continental shelf is the edge of a continent that lies under the ocean. Continents are the seven main divisions of land on Earth. A continental shelf extends from the coastline of a continent to a drop-off point called the shelf break. From the break, the shelf descends toward the deep ocean floor in what is called the continental slope. Even though they are underwater, continental shelves are part of the continent. The widths of the continental shelves vary.

Continental shelf

Continental slopes are regions of steeply sloping seafloor that lie between continental shelves and the deep ocean basins. Regional gradients are typically 2–5°, but locally slopes may be much steeper. Their large-scale morphology is a consequence of tectonic processes: the different elevations of continental crust and oceanic crust, the details of the original rift tectonics on passive continental margins, and the styles of subduction and accretion on convergent margins.

Continental rise

continental rise, a major depositional regime in oceans made up of thick sequences of continental material that accumulate between the continental slope and the abyssal plain. Continental rises form as a result of three sedimentary processes: mass wasting, the deposition from contour currents, and the vertical settling of clastic and biogenic particles.

Abyssal plane

The term ‘abyssal plain’ refers to a flat region of the ocean floor, usually at the base of a continental rise, where slope is less than 1:1000. It represents the deepest and flat part of the ocean floor lying between 4000 and 6500 m deep

Minor structures

Abyssal hills

An abyssal hill is a small hill that rises from the floor of an abyssal plain. They are the most abundant geomorphic structures on the planet Earth, covering more than 30% of the ocean floors. Abyssal hills have relatively sharply defined edges and climb to heights of no more than a few hundred meters. They can be from a few hundred meters to kilometers in width.

Trenches

Ocean trenches are steep depressions in the deepest parts of the ocean, where old ocean crust from one tectonic plate is pushed beneath another plate, raising mountains, causing earthquakes, and forming volcanoes on the seafloor and on land.

Submarine canyons

A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to 5 km, from canyon floor to canyon rim, as with the Great Bahama Canyon.

Ocean has several other wonders hid under its deep waters. If we go deeper new structures unfold.

The Bermuda Triangle

The Bermuda Triangle is a region in the north-western part of the Atlantic Ocean, near the USA. It is also called the ‘Devil’s Triangle’, because of all the disappearances and supernatural activity that is associated with it. Till date, around 50 ships and 20 airplanes have gone missing in the Bermuda triangle, never to be heard of again. Not even the wreckage or debris of any vessel has been found. One such case was in 1945, when a squadron of US Navy bombers became disoriented while flying over the area and thereafter disappeared, never to be found again. Even the rescue plane sent after them disappeared with no trace. No one knows what happens to the vessels, or the people inside them after entering the Bermuda triangle. Oftentimes the boats and planes have vanished without even sending out a distress call or signal, and planes have been known to go off the radar in this region of the ocean.

What are the possible explanations?

Many people like to suggest supernatural or other-worldly causes as possible explanations, like alien abductions or some mythical sea creature. However, it is more likely to have a scientific explanation, with geophysical and environmental factors at play. One such factor is that the agonic line (imaginary line connecting the earth’s north and south magnetic poles) passes through this area, which pilots may fail to account for. This may have caused discrepancies in interpreting the magnetic compass and thereby led to significant navigational error, resulting in catastrophe. Another scientific explanation is that the region often has massive rogue waves passing through it (reaching up to 100 feet) which are enough to carry away and engulf any evidence of a ship or airplane, which is why none has been found. Since multiple storms may converge in the Bermuda triangle, and hurricanes often sweep by in that area, it is possible to form massive waves and winds that destroy, carry away, and leave no sign of any vessels.

Furthermore, the National Oceanic and Atmospheric Administration of America has said that “There is no evidence that mysterious disappearances occur with any greater frequency in the Bermuda Triangle than in any other large, well-travelled area of the ocean,” This means that though there have been mysterious disappearances, a larger number of ships and airplanes have travelled through the region, and continue to do so today, without any incident. So, the few cases in which disappearances did occur might have been due to certain unfortunate circumstances and events.

Conclusion

There is a lot of mystery and fantasy involved when talking about the Bermuda triangle, but this is because human minds are drawn towards things that are bizarre and memorable, and we are more likely to remember things that seem exceptional in nature. In this process, however, we often disregard the ordinary things that offer a more realistic view. We prefer to think about a mysteriously disappearing ship rather than a ship that simply sank in a hurricane. This leads to something known as the ‘frequency illusion’ where once we’re introduced to something, we tend to notice it more often in our lives. This makes us believe that that thing is more common and frequent than it really is. Hence, the world may suffer from a frequency illusion that makes us want to think that the Bermuda triangle keeps swallowing up vessels very often, when in reality it has been a select few cases. In fact, mysterious disappearances happen in every part of the world, and not just the Bermuda triangle. The classic example of this being Malaysia Airlines flight 370.

Regardless, the Bermuda triangle has managed to capture human imagination with the unexplained disappearances in its area, and has also been referenced in may pop-culture pieces of media like the Gulliver’s Travels and Percy Jackson movies. This shows the impact that any strange phenomenon can have on human minds, and its ability to impress us. Today the Bermuda triangle is a safe destination that even tourists can visit to see for themselves, without any risk of disappearing.