What is Oceanic trench?
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What Does Oceanic trench Mean
The Latin word fodĕre , which can be translated as “dig” , became a fossa , which came to our language as a grave . This is what a cavity or excavation is called. Oceanic , for its part, is that linked to the ocean (the sea that separates the continents and that covers a large part of the surface of our planet).
The idea of an oceanic trench , in this framework, refers to a depression on the underwater floor that is located next to the continent or near the coasts of islands of volcanic origin. These sinkholes can have a depth of more than ten kilometers and present waters with temperatures between 0 ° C and 2 ° C.
The Pacific Ocean has the largest number of ocean trenches and those with the greatest depth . So far, the Mariana Trench is the deepest known oceanic trench. It is located southeast of the Mariana Islands , in the northwestern Pacific .
The deepest part of the Mariana Trench is known as the Challenger Deep . Throughout history there have been several expeditions to explore this place: in 2012 , filmmaker James Cameron reached depths of more than 10,898 meters in the Deepsea Challenger submersible .
Ocean trenches are generated when two tectonic plates meet and collide, causing the denser one to sink under the other. This phenomenon , known as subduction , causes the subsidence of the underwater floor: that is, it originates the oceanic trench.
The concept of subduction is under the tectonic plates , a theory of geology which serves to explain the way in which the lithosphere structure, ie, the rigid layer covering the surface of our planet. This process in which an oceanic zone of one plate sinks below the limit of another, takes place in a large number of subduction zones .
At present, almost all subduction zones are in the so-called Pacific ring of fire , although others can also be found in some regions of the Antilles, the Indonesian coast of Indonesia and the Mediterranean Sea. It is precisely in these areas that the oceanic trenches are formed, where the convergence and collision of two lithomeric plates occurs.
If we take the case of the Peru-Chile trench, also known by the name of the Atacama trench , we are facing a clear example of the consequence of a collision between two plates: the oceanic Nazca (a city located in southern Peru) and the continental South America.
In the subduction zones where the oceanic trenches are found, there is also a seismic activity of considerable intensity , which is caused by three phenomena led by the two plates: friction, compression and tension. All of this often starts with tsunamis and earthquakes in Indonesia and Japan, for example.
When the subduced plate reaches the asthenosphere (the upper part of the mantle that is under the lithosphere) it melts and in this state rises to give rise to a volcano . According to the characteristics of each plate, it is possible that the activity gives rise to arches of islands (a type of archipelago) or that a mountain range is generated , as are the cases of the Sunda Islands and the Mariana Trench. , respectively.
The Tonga Trench , the Japan Trench , the Kuril-Kamchatka Trench , the Philippine Trench and Kermadec Trench are other oceanic trenches more than ten kilometers deep. It should be noted that, despite being so deep, various species live in these graves .