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How do submarine rift valleys form along ocean ridges?

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tectonic basins and rift valleys Escarpments of the Great Rift Valley rising above the plain north of Samburu Game Preserve, central Kenya. Beisa oryxes graze in the foreground.

Submarine rift valleys form along ocean ridges as a result of plate tectonics at divergent boundaries, where two lithospheric plates move apart. As these plates separate, the Earth’s crust undergoes extension, causing it to fracture.123

This process leads to the formation of normal faults, where blocks of crust slide downward into the gap created by the diverging plates. This down-dropped block, known as a graben, creates the elongated trough characteristic of a rift valley.321

Simultaneously, these ridges serve as centers of seafloor spreading. Magma from the mantle wells up into the rift, cooling to form new oceanic crust that progressively moves away from the ridge crest. This continuous volcanic activity and crustal movement maintain the valley's structure, which often features relatively flat floors due to volcanic deposition and sedimentation.142