Here's why:
* Elastic deformation refers to a temporary change in the shape of a material that is reversible. The material will return to its original form once the stress causing the deformation is removed. Think of stretching a rubber band – it returns to its original length when you let go.
* Plastic deformation is a permanent change in shape. The material does not return to its original form after the stress is removed. Imagine bending a paper clip – it stays bent even after you release the force.
In the context of rock, elastic deformation is crucial for understanding how rocks behave under stress. This type of deformation allows rocks to absorb some energy from earthquakes and other geological events without fracturing. However, if the stress exceeds the rock's elastic limit, it will undergo plastic deformation or even fracture.
