The process of the seafloor spreading is the main theme on which the newer oceanic crust form or begins to develop and the rise of divergent plates from the mid-ocean zone also is responsible for the formation of the new plates on the floor.
<u>Thus due to these events the plates get created and the current spreading rate of the Atlantic ocean is thus widening and the pacific ocean crust is thus collapsing and the opening of the newer plate margins form the ocean deeps.
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This process is related to that of the paleomagnetism and the drifting away fo the super continental landmasses and thus the formation of the Americas and the closing of the Tethys sea.
Hence the seafloor spreading is a dynamic concept as it widens the oceanic basins and the plates spread from the new to the old areas.
Tensional stress occurs as a result of forces which could be wind, water etc pulling the rocks apart and forming faults. Faults are also known as a type of fracture which occurs between rocks.
Tensional stress along a fault can result in a dropped hanging-wall block relative to the footwall side(in a perpendicular position) thereby producing a normal fault.