Noun: When you sit in a diner booth and try to sneak a fart. The thump of the violently escaping flatulence makes a thud that can be felt by the person sitting next to you.
Don't sit next to Marc. His boothquakes average 8.2 on the rectum scale.
When a woman with shape moves her hiney in such a way that causes male arrousal.
This term was brought into common use with the Dr. Khan & DJ Bouti music video titled "bootyQuake".
Search for "bootyQuake" on www.youtube.com for Dr. Khan & DJ Bouti's music video.