* Plate Tectonics: Mid-ocean ridges are where new oceanic crust is formed as tectonic plates pull apart (diverge).

* Tensional Stress: This pulling apart creates tension in the Earth's crust, leading to tensional stress.

* Normal Faults: Tensional stress causes the hanging wall (rock block above the fault) to move downward relative to the footwall (rock block below the fault). This type of fault is known as a normal fault.

Visualizing Normal Faults at Mid-Ocean Ridges:

Imagine two plates pulling apart. The space created between them is filled with magma rising from the mantle. As this magma cools and solidifies, it creates new oceanic crust. This process stretches the existing crust, resulting in normal faults that create a series of valleys (rift valleys) and uplifted blocks.

Key Features of Normal Faulting at Mid-Ocean Ridges:

* Graben Formation: Normal faults often occur in sets, creating elongated, down-dropped blocks called grabens. The central valley of the mid-ocean ridge is typically a graben.

* Horst Formation: Uplifted blocks between grabens are known as horsts.

* Magma Upwelling: The normal faulting facilitates the rise of magma from the mantle, contributing to the formation of new oceanic crust.

In summary, normal faulting is the dominant type of faulting at mid-ocean ridges due to the tensional stress created by plate divergence and the associated process of new oceanic crust formation.