* Plate Movement: Earth's tectonic plates are constantly moving, albeit very slowly. This movement can be:
* Convergent: Plates collide, causing one to slide under (subduction) or buckle upwards (mountain building).
* Divergent: Plates pull apart, creating new crust (mid-ocean ridges).
* Transform: Plates slide past each other horizontally (like the San Andreas Fault).
* Stress Accumulation: As plates move, they create friction and pressure against each other. This constant push and pull results in the buildup of stress within the Earth's crust.
* Rock Deformity: The stress eventually exceeds the strength of the rocks along the fault lines. This causes the rocks to deform, either bending or fracturing.
* Rupture and Earthquake: When the stress overcomes the strength of the rocks, a sudden release of energy occurs – this is the earthquake. The rocks along the fault line shift and release the built-up energy in seismic waves, causing the ground to shake.
In essence, the constant movement and interaction of tectonic plates generate immense pressure and friction, creating the conditions necessary for earthquakes to occur along their boundaries.
