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Earthquakes The shaking of the Earth’s crust caused by a release of energy. The major cause is the build up of stress between two lithospheric plates. Sometimes plates moving past each other will lock, and over time stress builds. Plates begin to change shape and deform as well.
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Earthquakes The shaking of the Earth’s crust caused by a release of energy. The major cause is the build up of stress between two lithospheric plates. Sometimes plates moving past each other will lock, and over time stress builds. Plates begin to change shape and deform as well. Eventually, the stress becomes too much and the plate slips. This movement is what causes the earthquake. The plates that had become deformed snap back into their original shape. (This process is known as the Elastic Rebound Theory).
Folding and Faulting When lithospheric plates are put under stress, they react by folding or faulting. A fold occurs due to compressional stress or plates moving towards each other. 2 Basic Folds: • Anticline • Syncline
A fault is a crack or break in the Earth’s crust where movement has occurred. 3 Basic faults : • Normal • Reverse • Strike-slip
Anticline- An upwards fold. Syncline- A downward fold. Normal Fault- caused by tensional stress (crust is being pulled apart) and one rock plane drops down on one side of the fault. Reverse Fault- caused by compression stress (crust is being pushed together) and one rock plane rides up on one side of the fault. Strike-slip- caused by shear stress and the rocks on either side moved horizontally past each other.
