gravity blast refers to a drumming technique used exclusively in extreme metal. It is a one handed roll accomplished by boucing the stick off the rim of the snare drum while hitting the head of the snare drum in a continuous manner. Not to be confused with a regular blast beat which is just 32nd notes on one hand as fast as possible. When mastered a gravity blast sounds like an extremely rapid firing machine gun, perfect for backing apocalyptic demonic death metal riffs that make you wanna rape your mom and kill your dog while bathing in the blood of your failed messiah.
The gravity blast is used by bands such as Cryptopsy, Origin, Brain Drill, Vatic Ash just to name a few.