Well there are two P waves and S waves. P waves come first . then S waves come. P waves come from underground and S waves are above ground and move in the shape of an S and they are the ones that...
An earthquake is called an earthquake no matter whether it is small or large. An earth tremor is just a general term used by people to describe a small earthquake.
No. Earthquakes in a region do not generally coincide with those in another region. Epicenters will deviate somewhat with aftershocks, but not that significantly.