if you are talking about earthquakes then its all about tectonic plates. The force of two plates get to much so one of the plates slide under the other forming an earthquake.
The earth rotates and depending on the angle in regards to the sun will determine what season is felt at any given location on earth. The more direct sunlight the warmer and the less sunlight in an...
The Equatorial bulge is caused by movements in the core and mantle. The Earth, much like the sun, heaves (or "breathes") and causes the Equatorial bulge.