Here's why:
* Earth's Structure: The Earth is made up of layers: crust, mantle, outer core, and inner core. The vast majority of earthquakes occur in the crust and uppermost part of the mantle, in a zone called the lithosphere.
* Plate Tectonics: The Earth's lithosphere is broken into large plates that are constantly moving. When these plates collide, pull apart, or slide past each other, they cause stress to build up within the rocks.
* Fault Lines: This stress eventually exceeds the strength of the rocks, causing them to break and slip along fault lines. This sudden release of energy is what we feel as an earthquake.
* Hypocenter: The point beneath the Earth's surface where the earthquake originates is called the hypocenter or focus. The epicenter is the point on the Earth's surface directly above the hypocenter.
So, while we feel the effects of earthquakes on the surface, the actual break and movement of rocks happens deep underground.
