What causes an earthquake ?

An earthquake is caused by a sudden slip on a fault. ... When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earth's crust and cause the shaking that we feel. In California there are two plates - the Pacific Plate and the North American Plate.

Maybe on the physical part? i dunno i just guessed plus i really need the points

Aristotle thought so every portion of the earth tends toward the center until by compression and convergence they form a sphere. travelers going south see southern constellations rise higher above the horizon.~ hope this !