Here's why:
* Tensile stress: This is a type of stress that pulls on a material, stretching it. In the context of the Earth's crust, tensile stress occurs when tectonic plates move apart, creating a pulling force on the crust.
* Extensional stress: This is a broader term that describes stress that tends to lengthen or extend a material. It's often used interchangeably with tensile stress in the context of geology.
This pulling apart of the crust leads to the formation of:
* Rift valleys: These are long, narrow depressions in the Earth's surface, formed when tectonic plates move apart.
* Mid-ocean ridges: These are underwater mountain ranges formed at divergent plate boundaries, where new crust is created.
* Volcanoes: Volcanoes can form along rift valleys and mid-ocean ridges as magma rises from the mantle to fill the space created by the pulling apart of the crust.
