The San Andreas Fault Line is a sexual maneuver where a male spreads his partner's buttcheeks and proceeds to defecate in his partner's spread buttcrack. Once he has finished, he then presses his partners's buttcheeks together. He then proceeds to shake his partner's butt in any way he can, which can include but is not limited to shaking or slapping. While he is doing this, he is screaming "EARTHQUAKE". After he is finished, he calculates how much feces escaped the buttcrack during the earthquake and gives it a rating on the Richter Scale.

(noun) A successful type of theft which results in an acceptable, impressive and rewarding payday for the protagonist.