when an earthquake occurs, what is generated?

Question

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Answer 1

Seismic waves are the result of earthquakes, and they are the reason the ground shakes during an earthquake even if you are many miles away from the focus of the quake.

There are three kinds of seismic waves that result from an earthquake:

P-waves - "Primary waves", these are compressional energy waves that travel at about the speed of sound. They are usually the first seismic wave to arrive after an earthquake strikes. They can travel through solids as well as liquids.

S-waves - "Shear waves", these travel slower than the p-waves, but they are usually much more destructive than p-waves. These are the waves that cause the ground to move from one side to another and can only travel through solids (not liquids or gasses).

Surface waves - these are the most destructive of all seismic waves. They travel along the ground and cause the ground to roll sort of like the surface of the ocean. They are the last seismic waves to arive after an earthquake.

Answer 2

Mr Brooks answer is correct.But even in the surface wave we have 2 waves. Those are L wave which gives lateral movement only. Then comes the most dangerous wave called Raleigh wave. This will have rolling action. Richter scale 3 will shake 0.1 mm when it is sensed from the distance of 100 K/M. If the quake magnitude is 4 you will sense shaking of 1 mm. It will increase by 10 fold for every Richter scale. The energy release will be of the order of 32 times for each Richter scale.