Why do rift valleys occur?

Rift valleys are types of valleys that are typically long, narrow, and deep. They basically occur or form because of a land fault.  When part of the Earth’s surface, called the lithosphere starts to break apart, it will create a narrow valley between the split rock parts.  These valleys are then called rifts simply because of the way they are formed.  They differ from the usual river valleys that are mainly formed due to the Earth’s erosion.

Before the Earth’s crust will pull apart from each other, several plates will undergo thinning and erosion.  When the force of the thinning becomes excessive, the only tendency for the Earth’s crust is to split apart along a specific faultline.  This basically explains why rift valleys will be long and narrow from the start. Depending on the faultline that ripped apart, rift valleys could be formed for as long as 1,000 kilometers.  The typical formation is that of two parallel faults that split apart causing a break in the Earth’s crust.  The higher the tension in the fault, the deeper and bigger will be the rift formed.

When the rift valley is formed, it can also go wider and deeper depending on natural conditions.  Over long periods of time, natural soil erosion can contribute to the deepening and widening of rift valleys.  Raging water in rift valley rivers can also help make the rifts larger and wider over a long period of time.

Rift valleys may also form at various elevations.  It can be formed along faultlines that can be found in deep ocean floors.  Most rift valleys that people see are those that are formed on mountain ranges and flatlands.  These rift valleys could also stretch to more than 1,000 kilometers passing through different regions or countries.