What geological process causes earthquakes?

Answer 1

Earthquakes are caused by the build up or accumulation of pressure (more correctly termed stress).

This accumulation of stress causes the rocks that make up the crust to deform elastically. This is very similar to what happens when you squash or stretch a spring and causes a form of energy to be stored in the rocks of the crust - technically described as elastic potential energy.

When this stress gets to large, it exceeds the strength of the rocks in the crust and causes a brittle failure. Brittle failures are failures where fractures form through the material.

This sudden brittle failure causes all of the elastic potential energy to be released at one time in the form of seismic waves, just as if a spring or elastic band that was being stretched suddenly snapped.

These seismic waves cause the tremors that people feel on the surface and which can cause damage to buildings and other structures.

Answer 2

Well, there are lots of processes going on to make earthquakes happen. The crust (the solid part of the Earth, a very thin upper layer, which we stand on) is split into many "plates", so to speak. Along these plates are fault lines, and sometimes you find some of that stuff in the middle of the plates. The plates are in constant, but slow motion. Convection in the mantle (the layer of Earth just below the crust, slightly between liquid and solid) causes the liquid to move in a vertical circular pattern underneath the crust, and the portion that touches the crust can move in various directions. This is what moves the plates along, away from, or toward the other plates. This movement is known as Continental Drift. The plates, being rough, tend to stick to each other sometimes despite the mantle moving beneath them. This builds up tension, though, because the mantle wants to stick to the plates. When the tension builds up enough, the plates snap apart or slip past each other rather quickly, releasing a tremendous amount of energy referred to as an earthquake. The point where the energy is released is called the epicenter, and just above that is where people will say the center of the earthquake is, at least on the surface. The waves of energy can be felt around the world sometimes, if it's big enough, but there are some spots that receive no waves because of the way the waves bend through the center of the Earth (waves cannot penetrate the solid core of Earth, therefore there are "blind spots"). And there's more than you needed to know about earthquakes, but not all about earthquakes. There's a lot more than that to learn later on.

Answer 3

when the lemons fall off the trees they vibrate the earths surface which cause the earth to shake. this is called an earth quake. chicken.