The relief is the set of forms that the earth's surface presents. However, in the depths of the ocean there are also variations of the terrain and they are known by the name of oceanic relief.
Conformation and distribution of the oceanic relief
The dynamics of the inner layers of the earth originate both the continental and the oceanic relief. Mountains, ranges, hills, plains or plateaus are examples of continental relief.
Geographical accidents also appear in the underwater relief. Rounded, level shapes and gentle slopes predominate in them. On the other hand, the continental shelves are found in the depth of the sea and are the portions of the continent that continue under the waters until reaching 200 meters of depth.
The bathyal regions or zones extend where the continental shelf ends and reach approximately one thousand meters. Then come the abyssal regions, in which deposits with an organic origin predominate (these areas range from 1,000 to 5 meters). Finally, there are the marine trenches, which are the greatest depths of the oceanic type.
The oceanic relief has been changing throughout the history of the planet
It can be said that this evolution begins when a continental mass is fractured by the forces that pull it in opposite directions. This causes the subsidence of the region and the formation of an oceanic valley with a ridge in its center (these ridges are large mountain ranges and are the consequence of the movements of the oceanic crust plates).
On the ocean floor there is also volcanic activity
Volcanoes are not unique to the earth's surface. In fact, there are undersea volcanoes and some of them are active. An active underwater volcano could potentially trigger a tsunami.
The eruptions of underwater volcanoes are very powerful and their effects can be devastating (some of these volcanoes can form new islands). On the other hand, underwater volcanoes have regular cycles and due to this they can generate changes in the planet's climate.
To date, very few volcanic eruptions have been observed, but scientists believe that in the future this phenomenon will allow us to better understand the evolution of oceanic reliefs.
Photos: Fotolia - Shin / Beshencev
