[1] The ocean drum was originally called the geophone.
It was invented by composer and ornithologist Olivier Messiaen for his orchestral piece Des canyons aux étoiles... in 1972, inspired by the Native American water drum.
Soon after, the instrument began gaining more renown and is now commonly known by the term ocean drum.
The ocean drum is held by the frame, with the heads horizontal, and played by rolling the wrists so the drum gently tilts in all directions.
Stopping and starting suddenly creates crashing wave sounds.The ocean drum can be used in Buddhist meditation.