This is an area on earth where the lithospheric plates are moving away from each other, forming an extensive system of fractures and faults. is responsible for sea floor spreading.

The answer is Divergent boundary.

Explanation:

It is an are where two lithospheric plates move away from each other which results in cracks and faults. Divergent boundaries in the middle of the ocean contribute to sea floor spreading when plates made of oceanic crust move apart from each other resulting in the appearance of cracks in the ocean floor. Some of the divergent boundaries are the mid Atlantic ridge and the Great rift valley.